model questions
Long question 20 Marks each
1. Describe the Oparin Haldane theory of origin of life.
2. Describe the Mendel’s Laws of Inheritance.
3. Describe the theory of Natural selection with its limitation.
4. Discuss the various scopes of Natural science.
5. Discuss the strategies in the management of wildlife in Nepal.
6. What is Law of Independent Assortment? Describe it with dihybrid cross of Mendel’s experiment.
Short questions (attempt any five) 8 marks each
1. How is Chemistry related with Biology?
2. Write short notes on spontaneous generation.
3. Describe Miller Urey experiment about origin of life.
4. Illustrate the use and disuse of organ in Lamarckism
5. Write a short note on survival of the fittest.
6. Describe Redi’s experiment. How does it prove Biogenesis?
7. Give the meaning of a) Punnet Square b) Genotype
8. Describe the monohybrid cross of Mendel’s experiment.
9. Describe the dihybrid cross of Mendel’s experiment.
10. Why did Mendel select pea plant for his experiment.
11. Write down the role of forest.
12. Write down the role of the river.
13. Write short account of any one National Park of Nepal.
14. What are the causes of Flood.
15. What are the strategies in the management of landslides
16. What are the protective measures to be carried out at the time of earth quake?
17. Why are mountains important to us?
18. How are the Himalayas different from mountains?
19. Write short note on mountain ecosystem
20. Write consequences of deforestation
21. Write short notes on Special Creation Theory regarding origin of life.
22. The giraffe has long neck and long fore limb. What do this prove.?
23. Why have snakes lost legs?
24. Give name of four endangered animals of Nepal and causes of being endangered.
Sunday, September 19, 2010
Friday, March 19, 2010
for BSc II students
Linkage
Chromosomes take part in the transmission of hereditary characters through hereditary units or genes. An individual has usually many genes. So, we can say that one chromosome contains more than one gene. The genes for different characters may be either situated in same chromosome or in different chromosomes. If genes are situated in the same chromosome and are fairly close to each other then they tend to be inherited together. This type of coexistence of two or more genes in the same chromosome in known as linkage
The hypothesis that linked genes tend to remain in their original combination due to close location in the same chromosome was advanced by T H Morgan in 1911. Before Morgan, Sutton 1903 and Bateson and Punnet 1906 had given some hints about the phenomenon of linkage.
Types of linkage
T H Morgan and his co-workers by their investigations on the Drosophila and other organisms have found two types of linkage.
1. Complete linkage.
2. Incomplete linkage.
The complete linkage is the phenomenon in which parental combinations of characters appear together for two or more generations in a continuous and regular basis. In this case, the linked genes are closely associated and tend to transmit together.
Example The genes for bent wings (bt) and shaven bristles(svn) of the fourth chromosome (mutant) of Drosophila melanogaster exhibit complete linkage.
The linked genes do not always stay together because homologous non- sister chromatids may exchange segments of varying length with one another during meiotic prophase. This sort of exchange of chromosomal segments in between homologous chromosomes is known as crossing over. The linked genes which are widely located in chromosome and have chances of separation by crossing over is called incompletely linked genes and the phenomenon of their inheritance is called incomplete linkage.
Example linked genes for body color, black body (b) and grey body + and wing shape, vestigial (v) and long wing +
Linkage groups
All the linked genes of a chromosome form a linkage group. Linkage groups of a homologous chromosome are considered as one. The linkage group of a species corresponds with the haploid chromosome number of that species.
Example Drosophila has 4 pairs of chromosomes and 4 linkage groups
Man has 23 pairs of chromosomes and 23 linkage groups
Significance of linkage
The phenomenon of linkage has one of the great significance for the living organisms that it reduces the possibility of variability in gametes unless crossing over occurs.
Chromosomes take part in the transmission of hereditary characters through hereditary units or genes. An individual has usually many genes. So, we can say that one chromosome contains more than one gene. The genes for different characters may be either situated in same chromosome or in different chromosomes. If genes are situated in the same chromosome and are fairly close to each other then they tend to be inherited together. This type of coexistence of two or more genes in the same chromosome in known as linkage
The hypothesis that linked genes tend to remain in their original combination due to close location in the same chromosome was advanced by T H Morgan in 1911. Before Morgan, Sutton 1903 and Bateson and Punnet 1906 had given some hints about the phenomenon of linkage.
Types of linkage
T H Morgan and his co-workers by their investigations on the Drosophila and other organisms have found two types of linkage.
1. Complete linkage.
2. Incomplete linkage.
The complete linkage is the phenomenon in which parental combinations of characters appear together for two or more generations in a continuous and regular basis. In this case, the linked genes are closely associated and tend to transmit together.
Example The genes for bent wings (bt) and shaven bristles(svn) of the fourth chromosome (mutant) of Drosophila melanogaster exhibit complete linkage.
The linked genes do not always stay together because homologous non- sister chromatids may exchange segments of varying length with one another during meiotic prophase. This sort of exchange of chromosomal segments in between homologous chromosomes is known as crossing over. The linked genes which are widely located in chromosome and have chances of separation by crossing over is called incompletely linked genes and the phenomenon of their inheritance is called incomplete linkage.
Example linked genes for body color, black body (b) and grey body + and wing shape, vestigial (v) and long wing +
Linkage groups
All the linked genes of a chromosome form a linkage group. Linkage groups of a homologous chromosome are considered as one. The linkage group of a species corresponds with the haploid chromosome number of that species.
Example Drosophila has 4 pairs of chromosomes and 4 linkage groups
Man has 23 pairs of chromosomes and 23 linkage groups
Significance of linkage
The phenomenon of linkage has one of the great significance for the living organisms that it reduces the possibility of variability in gametes unless crossing over occurs.
Thursday, March 18, 2010
for BSc II students
Giant chromosomes
Some cells at particular stages contain large nucleus with giant or large sized chromosomes. The giant chromosomes are Polytene and lamp brush chromosomes.
Polytene chromosome
It occurs in the tissues of salivary gland, gut, trachea, fat body cells and Malpighian tubules of many insects of the order Diptera. It was first reported by E G Balbiani in 1881. The name polytene was suggested by Kollar due the occurrence of many chromonemata.
The polytene chromosomes are larger in size. The polytene chromosome of Drosophila melanogaster has total length of 200 microns in comparison to the 7.5 microns of somatic chromosome. The enormous size of the polytene chromosome is achieved by the duplication of chromonema for nine or ten times and duplicated chromonemata are not separated.
The polytene chromosome consists of closely coiled or associated homologus pairs of chromosomes. This association is called somatic pairing.
The polytene chromosome contains about 1000 times more DNA material than the somatic chromosomes.
Dark and light bands
Polytene chromosome bears alternating dark and light bands. The dark bands take deep stain with basic chromosomal stain and contains large amount of DNA and small amount of RNA. These are mainly composed of euchromatin. The light bands take light chromosomal stain and contains small amount of DNA and large amount of RNA. They are mainly composed of heterochromatin.
The polytene chromosome is caused by the process of endomitosis. In endomitosis, chromonemata become duplicated and resulted chromonemata do not separate to form new chromosome but remain closely associated. Also in endomitosis, nuclear membrane does not rupture and no spindle fibre formation takes place.
During development stages, polytene chromosome of larva of Dipterous insect, develop swelling at particular point of dark and light band. Such swelling is called puffs or bulbs. The puffing process involves accumulation of acidic protein, synthesis of RNA and storage of synthesized mRNA.
The chromonema of polytene chromosome gives out series of loops laterally. These rings are known as Balbiani rings. They are rich in DNA and mRNA. The formation of Balbiani rings are similar to puffs.
Lampbrush chromosome
The yolk rich oocytes of many vertebrates such as fishes, amphibians, reptiles and birds, contain exceptionally large sized chromosomes known as lamp brush chromosomes. They were discovered by Ruckert.
The lamp brush chromosomes are much longer. The length of lamp brush chromosome in Urodele oocyte may reach up to 5900 microns.
The lamp bush chromosomes are composed of the main axis and lateral loops. The main axis is composed of 4 chromatids or two bivalent chromosomes. The chromonemata of these chromaitd give out fine loops at lateral sides giving appearance of lamp brush or test tube brush.
The loops of lamp brush chromosomes are rich in RNA and protein. The RNA appears to be mRNA. The synthesis of protein and yolk take place near the loop.
Cytogenetical functions of chromosomes
Chromosomes are the most significant component of cell. They control most of the biological and genetical activities of cell. They contain genetical material, DNA which ultimately influences the biological phenomena atg molecular, physiological and gross morphological level.
Some cells at particular stages contain large nucleus with giant or large sized chromosomes. The giant chromosomes are Polytene and lamp brush chromosomes.
Polytene chromosome
It occurs in the tissues of salivary gland, gut, trachea, fat body cells and Malpighian tubules of many insects of the order Diptera. It was first reported by E G Balbiani in 1881. The name polytene was suggested by Kollar due the occurrence of many chromonemata.
The polytene chromosomes are larger in size. The polytene chromosome of Drosophila melanogaster has total length of 200 microns in comparison to the 7.5 microns of somatic chromosome. The enormous size of the polytene chromosome is achieved by the duplication of chromonema for nine or ten times and duplicated chromonemata are not separated.
The polytene chromosome consists of closely coiled or associated homologus pairs of chromosomes. This association is called somatic pairing.
The polytene chromosome contains about 1000 times more DNA material than the somatic chromosomes.
Dark and light bands
Polytene chromosome bears alternating dark and light bands. The dark bands take deep stain with basic chromosomal stain and contains large amount of DNA and small amount of RNA. These are mainly composed of euchromatin. The light bands take light chromosomal stain and contains small amount of DNA and large amount of RNA. They are mainly composed of heterochromatin.
The polytene chromosome is caused by the process of endomitosis. In endomitosis, chromonemata become duplicated and resulted chromonemata do not separate to form new chromosome but remain closely associated. Also in endomitosis, nuclear membrane does not rupture and no spindle fibre formation takes place.
During development stages, polytene chromosome of larva of Dipterous insect, develop swelling at particular point of dark and light band. Such swelling is called puffs or bulbs. The puffing process involves accumulation of acidic protein, synthesis of RNA and storage of synthesized mRNA.
The chromonema of polytene chromosome gives out series of loops laterally. These rings are known as Balbiani rings. They are rich in DNA and mRNA. The formation of Balbiani rings are similar to puffs.
Lampbrush chromosome
The yolk rich oocytes of many vertebrates such as fishes, amphibians, reptiles and birds, contain exceptionally large sized chromosomes known as lamp brush chromosomes. They were discovered by Ruckert.
The lamp brush chromosomes are much longer. The length of lamp brush chromosome in Urodele oocyte may reach up to 5900 microns.
The lamp bush chromosomes are composed of the main axis and lateral loops. The main axis is composed of 4 chromatids or two bivalent chromosomes. The chromonemata of these chromaitd give out fine loops at lateral sides giving appearance of lamp brush or test tube brush.
The loops of lamp brush chromosomes are rich in RNA and protein. The RNA appears to be mRNA. The synthesis of protein and yolk take place near the loop.
Cytogenetical functions of chromosomes
Chromosomes are the most significant component of cell. They control most of the biological and genetical activities of cell. They contain genetical material, DNA which ultimately influences the biological phenomena atg molecular, physiological and gross morphological level.
Monday, March 8, 2010
for Grade XII
Himalayan White House Int’l College
Grade XII
Model Question 2066 set I
Section A Zoology
1. Give very short answers of following questions any seven 1x7=7
1.1. From where does epithelial cell rise?
1.2. Which vitamin is called antisterility vitamin?
1.3. What is breathing rate in man?
1.4. What do you mean by double circulation?
1.5. Why is urine yellow in colour?
1.6. Which cranial nerve is mixed nerve?
1.7. What do the leydig cells secrete?
1.8. How is urea formed in liver?
1.9. What are psychedelic drugs?
1.10. What is in-vitro fertilization?
2. Give sort answers of following questions any five 3x5=15
2.1. Write how is CO2 transported?
2.2. Discuss benefits of genetic engineering.
2.3. Describe haversian canal system
2.4. How does liver act as a homeostatic organ? Discuss.
2.5. Name the hormones produced by adrenal gland and state their
functions.
2.6. Enumerate the problems of population explosion.
2.7. Describe the structure of frog’s gastrula.
3. Give an account of human heart suitable diagram 7.5
OR
Describe human excretory system with necessary diagrams.
4. What are communicable diseases? Discuss the causative agent, symptoms and control major of any one disease you have studied? 8
Section B Botany
1. Give very short answers of following questions any seven 1x7=7
1.1. What is central dogma?
1.2. Define polyploidy.
1.3. How is xylem arrange in dicot and monocot stem?
1.4. Give two examples of main C4- plants
1.5. What is triple fusion?
1.6. Define variation?
1.7. What is osmosis?
1.8. Define the term tissue culture
1.9. Name the hormone responsible for leaf and fruit fall.
1.10. Name dead tissue of the plant body.
2. Give sort answers of following questions any five 3x5=15
2.1. Explain Mendel’s principle of dominance.
2.2. Differentiate between clone and offspring.
2.3. Describe the embryogeny of dicot embryo with necessary deagram.
2.4. What is photosphorylation? Differentiate cyclic photophorylation with non-cyclic photophorylation.
2.5. Mention the importance of tissue culture technology.
2.6. Mention the functions of gibberlins.
2.7. Describe the importance of sterilization in plant tissue culture
3. Describe anatomical features of monocot stem with well labeled diagram. 7.5
OR
Describe light independent steps of photosynthesis and also mention its relation with the light phase.
4. Describe the mechanism of replication of DNA in the eukaryotic cell. 8
Himalayan White House Int’l College
Grade XII
Model Question 2066 set II
Section A Zoology
1. Give very short answers of following questions any seven 1x7=7
1.1. What is the average weight of human brain?
1.2. What is organ of corti?
1.3. What is micturition?
1.4. What is autograft?
1.5. What is the function of Leydig cells?
1.6. Give the function of carbonic anhydrase.
1.7. Name the hormone that regulates water absorption.
1.8. What are drug addiction?
1.9. Name the hormones secreted by ovary.
1.10. What is Rh factor?
2. Give sort answers of following questions any five 3x5=15
2.1. Write a note on Haversian canal system.
2.2. Mention the applications of biotechnology
2.3. Write the procedure of amniocentesis.
2.4. What are the differences between parasympathetic and sympathetic nerves?
2.5. Discuss the histological structure of human pancreas.
2.6 . Explain briefly when exactly the two heart sounds are produced. Name the instrument used to hear these sounds.
2.7. Why the transplanted organs rejected & what are are the means to prevent rejection?
2. Describe the development of frog from the zygote up to the formation of coelom. 7.5
3. Describe the causative agent, symptoms and preventive measures of the non-Communicable disease.
OR
Describe the human brain with suitable diagram. 8
Section B Botany
1. Give very short answers of following questions any seven 1x7=7
1.1. What do you know about operon?
1.2. Write two important methods of vegetative propagation.
1.3. How does photophoshorylation differ from oxidative phosphorylation?
1.4. Mention the role of yeast in fermentation process.
1.5. Write down the complementary RNA sequence of the DNA segment AATTAACCGA.
1.6. List two major application of tissue culture technique.
1.7. Name two plants used as bio-fertilizers.
1.8. Give the structure of ethylene.
1.9. What is a genetic code?
1.10. Write one important difference between dicot stem and monocot stem
2. Give sort answers of following questions any five 3x5=15
2.1. Write down the experiment to demonstrate unequal transpiration from two surfaces of dorsiventral leaf.
2.2. Give an account of micro-mutation.
2.3. Describe in brief the criss cross inheritance.
2.4. What are objectives of plant breeding?
2.5. Discuss physiological effects of auxins on the plant body.
2.6. Describe principle of fermentation technology with example.
2.7. Write six differences between dicot and monocot root.
3. Draw a well-labeled diagram of T.S. of dicot root. Discuss how it differs from that of a monocot. 7.5
OR
What is respiration? Explain the process of glycolysis in plants.
4. Discuss the mechanism of DNA-replication. 8
Grade XII
Model Question 2066 set I
Section A Zoology
1. Give very short answers of following questions any seven 1x7=7
1.1. From where does epithelial cell rise?
1.2. Which vitamin is called antisterility vitamin?
1.3. What is breathing rate in man?
1.4. What do you mean by double circulation?
1.5. Why is urine yellow in colour?
1.6. Which cranial nerve is mixed nerve?
1.7. What do the leydig cells secrete?
1.8. How is urea formed in liver?
1.9. What are psychedelic drugs?
1.10. What is in-vitro fertilization?
2. Give sort answers of following questions any five 3x5=15
2.1. Write how is CO2 transported?
2.2. Discuss benefits of genetic engineering.
2.3. Describe haversian canal system
2.4. How does liver act as a homeostatic organ? Discuss.
2.5. Name the hormones produced by adrenal gland and state their
functions.
2.6. Enumerate the problems of population explosion.
2.7. Describe the structure of frog’s gastrula.
3. Give an account of human heart suitable diagram 7.5
OR
Describe human excretory system with necessary diagrams.
4. What are communicable diseases? Discuss the causative agent, symptoms and control major of any one disease you have studied? 8
Section B Botany
1. Give very short answers of following questions any seven 1x7=7
1.1. What is central dogma?
1.2. Define polyploidy.
1.3. How is xylem arrange in dicot and monocot stem?
1.4. Give two examples of main C4- plants
1.5. What is triple fusion?
1.6. Define variation?
1.7. What is osmosis?
1.8. Define the term tissue culture
1.9. Name the hormone responsible for leaf and fruit fall.
1.10. Name dead tissue of the plant body.
2. Give sort answers of following questions any five 3x5=15
2.1. Explain Mendel’s principle of dominance.
2.2. Differentiate between clone and offspring.
2.3. Describe the embryogeny of dicot embryo with necessary deagram.
2.4. What is photosphorylation? Differentiate cyclic photophorylation with non-cyclic photophorylation.
2.5. Mention the importance of tissue culture technology.
2.6. Mention the functions of gibberlins.
2.7. Describe the importance of sterilization in plant tissue culture
3. Describe anatomical features of monocot stem with well labeled diagram. 7.5
OR
Describe light independent steps of photosynthesis and also mention its relation with the light phase.
4. Describe the mechanism of replication of DNA in the eukaryotic cell. 8
Himalayan White House Int’l College
Grade XII
Model Question 2066 set II
Section A Zoology
1. Give very short answers of following questions any seven 1x7=7
1.1. What is the average weight of human brain?
1.2. What is organ of corti?
1.3. What is micturition?
1.4. What is autograft?
1.5. What is the function of Leydig cells?
1.6. Give the function of carbonic anhydrase.
1.7. Name the hormone that regulates water absorption.
1.8. What are drug addiction?
1.9. Name the hormones secreted by ovary.
1.10. What is Rh factor?
2. Give sort answers of following questions any five 3x5=15
2.1. Write a note on Haversian canal system.
2.2. Mention the applications of biotechnology
2.3. Write the procedure of amniocentesis.
2.4. What are the differences between parasympathetic and sympathetic nerves?
2.5. Discuss the histological structure of human pancreas.
2.6 . Explain briefly when exactly the two heart sounds are produced. Name the instrument used to hear these sounds.
2.7. Why the transplanted organs rejected & what are are the means to prevent rejection?
2. Describe the development of frog from the zygote up to the formation of coelom. 7.5
3. Describe the causative agent, symptoms and preventive measures of the non-Communicable disease.
OR
Describe the human brain with suitable diagram. 8
Section B Botany
1. Give very short answers of following questions any seven 1x7=7
1.1. What do you know about operon?
1.2. Write two important methods of vegetative propagation.
1.3. How does photophoshorylation differ from oxidative phosphorylation?
1.4. Mention the role of yeast in fermentation process.
1.5. Write down the complementary RNA sequence of the DNA segment AATTAACCGA.
1.6. List two major application of tissue culture technique.
1.7. Name two plants used as bio-fertilizers.
1.8. Give the structure of ethylene.
1.9. What is a genetic code?
1.10. Write one important difference between dicot stem and monocot stem
2. Give sort answers of following questions any five 3x5=15
2.1. Write down the experiment to demonstrate unequal transpiration from two surfaces of dorsiventral leaf.
2.2. Give an account of micro-mutation.
2.3. Describe in brief the criss cross inheritance.
2.4. What are objectives of plant breeding?
2.5. Discuss physiological effects of auxins on the plant body.
2.6. Describe principle of fermentation technology with example.
2.7. Write six differences between dicot and monocot root.
3. Draw a well-labeled diagram of T.S. of dicot root. Discuss how it differs from that of a monocot. 7.5
OR
What is respiration? Explain the process of glycolysis in plants.
4. Discuss the mechanism of DNA-replication. 8
Saturday, March 6, 2010
for Grade XI
MODEL QUESTI0N FOR CLASS XI 2066
Sub - Biology set I Full marks 75
Time 3 hours Pass mark 27
Section A Zoology
Q.no.1.Give answer in very brief (any seven) . 1X7=7
1.1 Differentiate between anadromous migration and catadromous migration in fishes .
1.2 How is biology related to chemistry ?
1.3 Name the excretory organ found in Platyhelminthes and annelids
1.4 Name the muscles that controls the movement of setae of earthworm .
1.5 What is the function of choanoderm in Porifera?
1.6 What do you mean by atavism ?
1.7 What is cyclosis?
1.8. What is the omentum?
1.9. What is the function of meganucleus in Paramecium?
1.10. What are the analogous organs for?
Q.No.2. Give the short answer of the following. .(any five) 3x5=15
2.1 Differentiate between old world monkey and new world monkey.
2.2 Discuss the economical importance of Earthworm.
2.3 Describe the aquatic adaptation feature of fishes .
2.4 What are the functions of pancreas in frog?
2.5. Describe the effects of air pollution on human body.
2.6. Discuss the structure of liver of frog.
2.7. Describe the sporogony in the life cycle of Plasmodium.
Q.No.3. Describe the structure and working mechanism of the heart of frog. [8]
OR
Describe the structure of digestive organ of Pheretima.
Q.No.4.Write an account of human evolution starting from Ramapethicus . [7.5]
Section B Botany
Q.No.1.Give answer in very brief (any seven). [1X7]
1.1. What is syngenesious stamen .
1.2. In which case there is inverted ecological pyramid present ?
1.3. What is coenocytic mycelium?
1.4. Give the full form of ADP and AMP
1.5.What are leucoplast?Mention their function
1.6. Write the function of heterosyst in Nostoc
1.7. Define crossing over.
1.8. What is flower?
1.9. What is cone?
1.10 Give any two functions of Golgi body.
Q.No.2. Give the short answer of the following. .(any five) 5x3=15
2.1. Name the different biotic components of the pond ecosystem
2.2 What are the economical nature of Bacteria
2.3. Describe the structure and function of chloroplast.
2.4. Discuss the consequence of ozone layer depletion .
2.5. Draw well labeled diagram of cynobacterical cell. No description required.
2.6. What is placentation? Mention their types with example.
2.7. Write the short comings of two kingdom system of classification.
Q.No.3. Write the distinguishing character of family Cruciferae with floral diagram and formula. Give the botanical names of any three economically plants . [8]
OR
Define alternaion of generation .Discuss it with reference to diagrammatic life cycle of Funaria 1+3+4
Q.No.4. Define food chain .Discuss it with reference of pond system . [7.5]
MODEL QUESTI0N FOR CLASS XI 2066
Set II
Sub - Biology Full marks 75
Time 3 hours Pass mark 27
Section A Zoology
Q.No.1.Give answer in very brief(any seven) . 1X7=7
1.1 What was the kind of atmosphere in the primitive earth?
1.2 Who coined the term Biology?
1.3. Who used the phrase “ survival of the fittest” for the first time?
1.4. What is the function of omentum?
1.5. Name the theory given by Hugo de Vries.
1.6.Why protoplasmic bridge are formed in Paracemium?
1.7. What are the characters for the fossorial adaptation?
1.8. What is the function of typhlosole in earthworm?
1.9. In which group of animal, do you find the stinging cells?
1.10. Who propounded the new theory regarding the flow of blood in the heart?
Q.No.2. Give the short answer of the following. .(any five) 3x5=15
2.1. Write short note on erythrocytic schizogony.
2.2. Give the general characters and classification of Arthropoda.
2.3. What are the causes of extinction of wildlife in Nepal.
2.4.Discuss protein as biomolecule.
2.5 Describe the asexual reproduction in Paramecium
2.6. Describe the spontaneous generation theory.
2.7. Discuss the old theory regarding the flow of blood in forg.
Q.No.3. Give a brief account of human evolution. [8]
Q.No.4. Discuss the physiology of digestion in frog. 7.5 Or
Describe reproductive system of earthworm.
Section B Botany
Q.No.1.Give answer in very brief (any seven). [1X7]
1.1. Define cellular totipotency.
1.2. Why is mitochondrion called the power house of cell?
1.3 Write down the functions of chloroplast.
1.4 Why are the nucleic acids are important for life?
1.5. What do you mean by scalariform conjugation?
1.6 Give one difference between corolloid root and mycorrhizal root
1.7. What is leaf?
1.8. What is the role of producers in Ecosystem?
1.9. Why is Spirogyra called water silk?
1.10 Give any two important characters of Kingdom Monera
Q.No.2. Give the short answer of the following.(any five). 5x3=15
2.1. Draw well labled diagram of cynobacterical cell. No description required.
2.2. Discuss the roles of edaphic factors in the ecosystem
2.3 Explain the characters of plant community.
2.4 Discuss protein as biomolecule.
2.5 Give an out line classification of 5 kingdom system. Mention its advantages and
disadvantages.
2.6 Briefly describe the economic importance of Bacteria
2.7. What do you mean by the following terms? A) Epipetalous B) Cruciform corolla C) Didelphous stamens
Q.No.3. . Give the salient features of Solanacae in semitechnical terms with its floral formula, diagram and two scientific names of economically important plants of this family. 8 Or
What is pollution ? Describe water pollution, their effect and control measures
Q.No.4. Describe the sexual reproduction in Mucor [7.5]
MODEL QUESTI0N FOR CLASS XI 2066
Sub - Biology set III Full marks 75
Time 3 hours Pass mark 27
Section A Zoology
Q.No.1.Give answer in very brief(any seven) . 1X7=7
1.1 What is incubation period?
1.2 What is the function of seminal vesicle in earthworm?
1.3 Write down the two endangered species of animals with scientific names
1.4 What is the gist of Lamarckism?
1.5 What do you mean by cyclosis in Paramecium?
1.6 What do the homologous organs show?
1.7 What do you understand by convergent evolution?
1.8.What is the function of fat bodies in reproduction?
1.9. What is physiology and cytology?
1.10. Why are the Protozoans immortal?
Q.No.2. Give the short answer of the following. .(any five) 3x5=15
2.1 Write down the conservation strategies of wild life.
2.2 Illustrate the functions of liver.
2.3. Why Archaeopteryx is regarded as connecting link?
2.4 Discuss the new theory regarding the flow of blood from auricles to ventricle in frog.
2.5 Describe the Urey Miller experiment with diagram.
2.6. Describe the cocoon formation in earthworm.
2.7. Describe the Erythrocytic cycle of Plasmodium.
Q.No.3.. Discuss the Theory of Natural Selection with its draw backs 8
OR
What is conjugation? Describe the process of conjugation in Paramecium. 7.5
Q.No.4.Describe the Amphibian Heart with suitable diagram.
Section B Botany
Q.No.1.Give answer in very brief(any seven) . [1X7]
1.1. Name the colouring pigment of red algae.
1.2 What is symbiosis? Give examples.
1.3 What are the bioindicators of air pollution?
1.4 Write down the names of subunits of prokaryotic ribosomes.
1.5 Write one major character of metaphase of mitosis.
1.6. Name two species of Pinus found in Nepal.
1.7. Give two importances of Cyanobaceteria.
1.8. What is phylotaxy?
1.9. Give the classification of Cycas.
1.10 Who gave the concept of totipotency and cell theory?
Q.No.2. Give the short answer of the following. .(any five) 5x3=15
2.1. Name the different biotic components of the pond ecosystem
2.2 What are the economical nature of Bacteria
2.3. Describe the structure and function of mitochondria.
2.4. Differentiate between primary and secondary succession.
2.5. Describe the impacts of deforestation.
2.6. What is aestivation? Discuss their types.
2.7 Describe cell structure of Spirogyra with well labeled diagram.
Q.No.3. What is Describe cell structure of Spirogyra with well labeled diagram.
biogeochemical cycle? Mention its types, also explain Nitrogen cycle in nature. 8 Or
Describe Papilionaceae or in semitechnical terms with it floral formula & floral diagram. Write any four economically important plant ofthis family with scientific names.
Q.No.4. What is alternation of generation? Describe it with reference of Fern. 7.5
MODEL QUESTI0N FOR CLASS XI 2066
Sub - Biology set IV Full marks 75
Time 3 hours Pass mark 27
Section A Zoology
Q.No.1.Give answer in very brief (any seven). 1X7=7
1.1.What is Anatomy?
1.2Write two important characteristic features of Phylum Echinodermata.
1.3What is the function of mesorchium?
1.4.Write the zoological names of Prawn and Spider.
1.5What is typhlosole? Mention its function.
1.6Write down the name of aminoacids found at the end of Miller and Urey’s experiment.
1.7What is the immediate ancestor of modern man
1.8. What is the method of asextual method in Paramecium?
1.9. What is she homodont?
1.10. At what time, Ramapethicus survived on the earth?
Q.no.2. Give the short answer of the following. .(any five) 5x3=15
2.1Give brief account of Reflex Action.
2.2Justify “ Earthworms are the friend of farmers”.
2.3Write a short note on Oparin and Haldane’s theory on Origin of life.
2.4Write down the causes of depletion of wild life.
2.5Give out line classification of Coelenterata with examples
2.6. Differentiate between Ape and Man
2.7. Describe the structure of tooth of frog.
Q.No.3.Describe the Theory of Natural Selection with its draw backs. 8
Q.No.4. Discuss the asexual life cycle of Plasmodium in man with well labeled diagram
Or
Describe the male reproductive system of Frog with labeled diagram. 7.5
Section B Botany
Q.No.1.Give answer in very brief(any seven) . [1X7]
1.1Why is deuteromycetes called fungi imperfecti?
1.2 Give the common names of Spirogyra and Funaria.
1.3What are the roles of decomposers in ecosystem?
1.4What are vascular cryptogams?
1.5. Define cell division.
1.6How are red algae able to survive and lead a successful life in deep sea?
1.7Name the pigments that are present in photoautotrophic bacteria
1.8. What do you mean by sporophyll?
1.9. Give any two xerophytic characters of Gymnoperm.
1.10.Give one difference between actinomorphic and zygomorphic flower.
Q.No.2. Give the short answer of the following.(any five). 5x3=15
2.1 Why are the viruses called Biological puzzles?
2.2.Differentiate between mitosis and meiosis cell division.
2.3.Explain haplo diplobiontic type of life cycle of yeast.
2.4.Draw a well labeled diagram of LS of capsule of Funaria.
2.5.Protein is one of the important biomolecule. Justify this statement
2.6. What is acid rain? Give its consequences.
2.7. Draw the phyllogenetic and evolutionary line of five kingdom system of classification.
Q.No.3.Describe the family Poaceae in semi technical terms with their floral diagram and floral formula . write any two plants belonging to this family with economic importance 8 Or
Describe the diagrammatic life cycle of Marchantia
Q.No.4. Describe the pond as an example of aquatic ecosystem with suitable diagram 7.5
MODEL QUESTI0N FOR CLASS XI 2066
Sub - Biology Set V Full marks 75
Time 3 hours Pass mark 27
Section A Zoology
Q.No.1.Give answer in very brief (any seven). 1X7=7
1.1. What is metamerical segmentation?
1.2. Give the meaning of plasmogamy and karyogamy
1.3. What is cyclosis?
1.4. What is physiology?
1.5. What is serological test carried out for?
1.6. Define the organic evolution and connecting link.
1.7. Classify Paramecium in scientific position.
1.8. Which artery supplies blood to the brain in frog?
1.9. What is the function of gizzard in earthaworm?
1.10. What is rare animal? Give example.
Q.No.2. Give the short answer of the following. .(any five) 5x3=15
2.1. Describe the Oparin and Haldane theory of origin of life on earth.
2.2. Draw a well labeled diagram of Frog.
2.3 Define endangered and vulnerable species and give the scientific name of any four endangered mammals of Nepal.
2.4. Discuss how the fossils give the evidences of organic evolution.
2.5. Earthworms are fiends of farmers. Justify.
2.6. Differentiate between cartilaginous and bony fishes.
2.7. Write down the characters of Phylum Mollusca.
Q.No.3. What is conjugation? Describe the process of conjugation in Paramecium 7.5
Or
What is portal system? Describe it with reference to frog.
Q.No.4.What is organic evolution? Trace out evolution of man starting from Ramapethicus. 8
Section B Botany
Q.No.1.Give answer in very brief (any seven). [1X7]
1.1. Lysosome is also called suicidal bag of cell, why?
1.2. Where is arghegonium formed in Funaria?
1.3. Give chief function of Ribosome.
1.4. Write two important character of Monera.
1.5. Mention one important difference between red and brown algae.
1.6. Write the function of heterocyst in nostoc.
1.7. Give the characteristic feature of Anaphase and Telophase of Mitosis.
1.8. What is leaf?
1.9. Give one difference between microsporophyll and megasporophyll
1.10. Which chemical give the rigidity to the cell wall.
Q.No.2. Give the short answer of the following.(any five) 5x3=15
2.1. Describe the asexual reproduction in Mucor.
2.2 Explain microgametogenesis.
2.3 Descrithe the structure and function of chloroplast.
2.4. Draw and describe the gametophyte of fern in short.
2.5. What is the modern trend in Taxonomy?
2.6. Write notes on medicinal and agricultural values of Bacteria.
2.7. Describe the different types of phylotaxy
Q.No.3.Describe the mitotic cell division 7.5
Q.No.4. Describe the life cycle of Spirogyra. 8 Or
Describe the family Solanaceae in semi technical terms with their floral diagram and floral formula . Write any two plants belonging to this family with economic importance
Sub - Biology set I Full marks 75
Time 3 hours Pass mark 27
Section A Zoology
Q.no.1.Give answer in very brief (any seven) . 1X7=7
1.1 Differentiate between anadromous migration and catadromous migration in fishes .
1.2 How is biology related to chemistry ?
1.3 Name the excretory organ found in Platyhelminthes and annelids
1.4 Name the muscles that controls the movement of setae of earthworm .
1.5 What is the function of choanoderm in Porifera?
1.6 What do you mean by atavism ?
1.7 What is cyclosis?
1.8. What is the omentum?
1.9. What is the function of meganucleus in Paramecium?
1.10. What are the analogous organs for?
Q.No.2. Give the short answer of the following. .(any five) 3x5=15
2.1 Differentiate between old world monkey and new world monkey.
2.2 Discuss the economical importance of Earthworm.
2.3 Describe the aquatic adaptation feature of fishes .
2.4 What are the functions of pancreas in frog?
2.5. Describe the effects of air pollution on human body.
2.6. Discuss the structure of liver of frog.
2.7. Describe the sporogony in the life cycle of Plasmodium.
Q.No.3. Describe the structure and working mechanism of the heart of frog. [8]
OR
Describe the structure of digestive organ of Pheretima.
Q.No.4.Write an account of human evolution starting from Ramapethicus . [7.5]
Section B Botany
Q.No.1.Give answer in very brief (any seven). [1X7]
1.1. What is syngenesious stamen .
1.2. In which case there is inverted ecological pyramid present ?
1.3. What is coenocytic mycelium?
1.4. Give the full form of ADP and AMP
1.5.What are leucoplast?Mention their function
1.6. Write the function of heterosyst in Nostoc
1.7. Define crossing over.
1.8. What is flower?
1.9. What is cone?
1.10 Give any two functions of Golgi body.
Q.No.2. Give the short answer of the following. .(any five) 5x3=15
2.1. Name the different biotic components of the pond ecosystem
2.2 What are the economical nature of Bacteria
2.3. Describe the structure and function of chloroplast.
2.4. Discuss the consequence of ozone layer depletion .
2.5. Draw well labeled diagram of cynobacterical cell. No description required.
2.6. What is placentation? Mention their types with example.
2.7. Write the short comings of two kingdom system of classification.
Q.No.3. Write the distinguishing character of family Cruciferae with floral diagram and formula. Give the botanical names of any three economically plants . [8]
OR
Define alternaion of generation .Discuss it with reference to diagrammatic life cycle of Funaria 1+3+4
Q.No.4. Define food chain .Discuss it with reference of pond system . [7.5]
MODEL QUESTI0N FOR CLASS XI 2066
Set II
Sub - Biology Full marks 75
Time 3 hours Pass mark 27
Section A Zoology
Q.No.1.Give answer in very brief(any seven) . 1X7=7
1.1 What was the kind of atmosphere in the primitive earth?
1.2 Who coined the term Biology?
1.3. Who used the phrase “ survival of the fittest” for the first time?
1.4. What is the function of omentum?
1.5. Name the theory given by Hugo de Vries.
1.6.Why protoplasmic bridge are formed in Paracemium?
1.7. What are the characters for the fossorial adaptation?
1.8. What is the function of typhlosole in earthworm?
1.9. In which group of animal, do you find the stinging cells?
1.10. Who propounded the new theory regarding the flow of blood in the heart?
Q.No.2. Give the short answer of the following. .(any five) 3x5=15
2.1. Write short note on erythrocytic schizogony.
2.2. Give the general characters and classification of Arthropoda.
2.3. What are the causes of extinction of wildlife in Nepal.
2.4.Discuss protein as biomolecule.
2.5 Describe the asexual reproduction in Paramecium
2.6. Describe the spontaneous generation theory.
2.7. Discuss the old theory regarding the flow of blood in forg.
Q.No.3. Give a brief account of human evolution. [8]
Q.No.4. Discuss the physiology of digestion in frog. 7.5 Or
Describe reproductive system of earthworm.
Section B Botany
Q.No.1.Give answer in very brief (any seven). [1X7]
1.1. Define cellular totipotency.
1.2. Why is mitochondrion called the power house of cell?
1.3 Write down the functions of chloroplast.
1.4 Why are the nucleic acids are important for life?
1.5. What do you mean by scalariform conjugation?
1.6 Give one difference between corolloid root and mycorrhizal root
1.7. What is leaf?
1.8. What is the role of producers in Ecosystem?
1.9. Why is Spirogyra called water silk?
1.10 Give any two important characters of Kingdom Monera
Q.No.2. Give the short answer of the following.(any five). 5x3=15
2.1. Draw well labled diagram of cynobacterical cell. No description required.
2.2. Discuss the roles of edaphic factors in the ecosystem
2.3 Explain the characters of plant community.
2.4 Discuss protein as biomolecule.
2.5 Give an out line classification of 5 kingdom system. Mention its advantages and
disadvantages.
2.6 Briefly describe the economic importance of Bacteria
2.7. What do you mean by the following terms? A) Epipetalous B) Cruciform corolla C) Didelphous stamens
Q.No.3. . Give the salient features of Solanacae in semitechnical terms with its floral formula, diagram and two scientific names of economically important plants of this family. 8 Or
What is pollution ? Describe water pollution, their effect and control measures
Q.No.4. Describe the sexual reproduction in Mucor [7.5]
MODEL QUESTI0N FOR CLASS XI 2066
Sub - Biology set III Full marks 75
Time 3 hours Pass mark 27
Section A Zoology
Q.No.1.Give answer in very brief(any seven) . 1X7=7
1.1 What is incubation period?
1.2 What is the function of seminal vesicle in earthworm?
1.3 Write down the two endangered species of animals with scientific names
1.4 What is the gist of Lamarckism?
1.5 What do you mean by cyclosis in Paramecium?
1.6 What do the homologous organs show?
1.7 What do you understand by convergent evolution?
1.8.What is the function of fat bodies in reproduction?
1.9. What is physiology and cytology?
1.10. Why are the Protozoans immortal?
Q.No.2. Give the short answer of the following. .(any five) 3x5=15
2.1 Write down the conservation strategies of wild life.
2.2 Illustrate the functions of liver.
2.3. Why Archaeopteryx is regarded as connecting link?
2.4 Discuss the new theory regarding the flow of blood from auricles to ventricle in frog.
2.5 Describe the Urey Miller experiment with diagram.
2.6. Describe the cocoon formation in earthworm.
2.7. Describe the Erythrocytic cycle of Plasmodium.
Q.No.3.. Discuss the Theory of Natural Selection with its draw backs 8
OR
What is conjugation? Describe the process of conjugation in Paramecium. 7.5
Q.No.4.Describe the Amphibian Heart with suitable diagram.
Section B Botany
Q.No.1.Give answer in very brief(any seven) . [1X7]
1.1. Name the colouring pigment of red algae.
1.2 What is symbiosis? Give examples.
1.3 What are the bioindicators of air pollution?
1.4 Write down the names of subunits of prokaryotic ribosomes.
1.5 Write one major character of metaphase of mitosis.
1.6. Name two species of Pinus found in Nepal.
1.7. Give two importances of Cyanobaceteria.
1.8. What is phylotaxy?
1.9. Give the classification of Cycas.
1.10 Who gave the concept of totipotency and cell theory?
Q.No.2. Give the short answer of the following. .(any five) 5x3=15
2.1. Name the different biotic components of the pond ecosystem
2.2 What are the economical nature of Bacteria
2.3. Describe the structure and function of mitochondria.
2.4. Differentiate between primary and secondary succession.
2.5. Describe the impacts of deforestation.
2.6. What is aestivation? Discuss their types.
2.7 Describe cell structure of Spirogyra with well labeled diagram.
Q.No.3. What is Describe cell structure of Spirogyra with well labeled diagram.
biogeochemical cycle? Mention its types, also explain Nitrogen cycle in nature. 8 Or
Describe Papilionaceae or in semitechnical terms with it floral formula & floral diagram. Write any four economically important plant ofthis family with scientific names.
Q.No.4. What is alternation of generation? Describe it with reference of Fern. 7.5
MODEL QUESTI0N FOR CLASS XI 2066
Sub - Biology set IV Full marks 75
Time 3 hours Pass mark 27
Section A Zoology
Q.No.1.Give answer in very brief (any seven). 1X7=7
1.1.What is Anatomy?
1.2Write two important characteristic features of Phylum Echinodermata.
1.3What is the function of mesorchium?
1.4.Write the zoological names of Prawn and Spider.
1.5What is typhlosole? Mention its function.
1.6Write down the name of aminoacids found at the end of Miller and Urey’s experiment.
1.7What is the immediate ancestor of modern man
1.8. What is the method of asextual method in Paramecium?
1.9. What is she homodont?
1.10. At what time, Ramapethicus survived on the earth?
Q.no.2. Give the short answer of the following. .(any five) 5x3=15
2.1Give brief account of Reflex Action.
2.2Justify “ Earthworms are the friend of farmers”.
2.3Write a short note on Oparin and Haldane’s theory on Origin of life.
2.4Write down the causes of depletion of wild life.
2.5Give out line classification of Coelenterata with examples
2.6. Differentiate between Ape and Man
2.7. Describe the structure of tooth of frog.
Q.No.3.Describe the Theory of Natural Selection with its draw backs. 8
Q.No.4. Discuss the asexual life cycle of Plasmodium in man with well labeled diagram
Or
Describe the male reproductive system of Frog with labeled diagram. 7.5
Section B Botany
Q.No.1.Give answer in very brief(any seven) . [1X7]
1.1Why is deuteromycetes called fungi imperfecti?
1.2 Give the common names of Spirogyra and Funaria.
1.3What are the roles of decomposers in ecosystem?
1.4What are vascular cryptogams?
1.5. Define cell division.
1.6How are red algae able to survive and lead a successful life in deep sea?
1.7Name the pigments that are present in photoautotrophic bacteria
1.8. What do you mean by sporophyll?
1.9. Give any two xerophytic characters of Gymnoperm.
1.10.Give one difference between actinomorphic and zygomorphic flower.
Q.No.2. Give the short answer of the following.(any five). 5x3=15
2.1 Why are the viruses called Biological puzzles?
2.2.Differentiate between mitosis and meiosis cell division.
2.3.Explain haplo diplobiontic type of life cycle of yeast.
2.4.Draw a well labeled diagram of LS of capsule of Funaria.
2.5.Protein is one of the important biomolecule. Justify this statement
2.6. What is acid rain? Give its consequences.
2.7. Draw the phyllogenetic and evolutionary line of five kingdom system of classification.
Q.No.3.Describe the family Poaceae in semi technical terms with their floral diagram and floral formula . write any two plants belonging to this family with economic importance 8 Or
Describe the diagrammatic life cycle of Marchantia
Q.No.4. Describe the pond as an example of aquatic ecosystem with suitable diagram 7.5
MODEL QUESTI0N FOR CLASS XI 2066
Sub - Biology Set V Full marks 75
Time 3 hours Pass mark 27
Section A Zoology
Q.No.1.Give answer in very brief (any seven). 1X7=7
1.1. What is metamerical segmentation?
1.2. Give the meaning of plasmogamy and karyogamy
1.3. What is cyclosis?
1.4. What is physiology?
1.5. What is serological test carried out for?
1.6. Define the organic evolution and connecting link.
1.7. Classify Paramecium in scientific position.
1.8. Which artery supplies blood to the brain in frog?
1.9. What is the function of gizzard in earthaworm?
1.10. What is rare animal? Give example.
Q.No.2. Give the short answer of the following. .(any five) 5x3=15
2.1. Describe the Oparin and Haldane theory of origin of life on earth.
2.2. Draw a well labeled diagram of Frog.
2.3 Define endangered and vulnerable species and give the scientific name of any four endangered mammals of Nepal.
2.4. Discuss how the fossils give the evidences of organic evolution.
2.5. Earthworms are fiends of farmers. Justify.
2.6. Differentiate between cartilaginous and bony fishes.
2.7. Write down the characters of Phylum Mollusca.
Q.No.3. What is conjugation? Describe the process of conjugation in Paramecium 7.5
Or
What is portal system? Describe it with reference to frog.
Q.No.4.What is organic evolution? Trace out evolution of man starting from Ramapethicus. 8
Section B Botany
Q.No.1.Give answer in very brief (any seven). [1X7]
1.1. Lysosome is also called suicidal bag of cell, why?
1.2. Where is arghegonium formed in Funaria?
1.3. Give chief function of Ribosome.
1.4. Write two important character of Monera.
1.5. Mention one important difference between red and brown algae.
1.6. Write the function of heterocyst in nostoc.
1.7. Give the characteristic feature of Anaphase and Telophase of Mitosis.
1.8. What is leaf?
1.9. Give one difference between microsporophyll and megasporophyll
1.10. Which chemical give the rigidity to the cell wall.
Q.No.2. Give the short answer of the following.(any five) 5x3=15
2.1. Describe the asexual reproduction in Mucor.
2.2 Explain microgametogenesis.
2.3 Descrithe the structure and function of chloroplast.
2.4. Draw and describe the gametophyte of fern in short.
2.5. What is the modern trend in Taxonomy?
2.6. Write notes on medicinal and agricultural values of Bacteria.
2.7. Describe the different types of phylotaxy
Q.No.3.Describe the mitotic cell division 7.5
Q.No.4. Describe the life cycle of Spirogyra. 8 Or
Describe the family Solanaceae in semi technical terms with their floral diagram and floral formula . Write any two plants belonging to this family with economic importance
Tuesday, February 16, 2010
for Grade XII
Physiology of circulation
Human body is fairly complex and performs wide range of activities. Different organs of body are located far away and may have no connection at all. Our body needs a specialized system of circulation which can connect these organs supplying nutrients, gases, hormones and carrying wastes from these organs. This system of circulation also performs the functions like regulation of things and protection. The system of circulation of some extra cellular fluid is flowing in the body. The structures associated with circulation constitute circulatory system.
Circulatory system must have these basic features
3. A pumping mechanism like heart.
4. A system of tubes through which the circulating fluid can move.
5. Presence of transporting or circulating fluid like blood or lymph.
Structure of heart
A human heart is muscular hollow pumping organ which can maintain continuous flow of blood circulation inside the body. It is roughly triangular in shape. It is about the size of a person’s fist and weighs about 300 grams. It is reddish brown in color. It is situated ventrally in the middle of thoracic cavity in between two lungs. The narrow end of the heart is slightly displaced to the left side. It can be heard towards the left side of the chest.
The heart is enclosed in a double walled membranous sac called pericardium. The inner membrane is attached to the heart. In between two membranes, there is presence of a pericardial fluid. The fluid is shock absorbing so protect heart from any shock and minor injuries. It also allows free movement to the heart.
Anterior broad part is called auricular part and posterior narrow part is called ventricular part. Towards right side of auricular part there is superior and inferior venacavae carrying impure blood from different parts of body except lungs. Towards the left side of auricular part, the pulmonary veins carry pure blood from lungs. The auricular part receives blood. The lower ventricular part sends out blood. The arch of Aorta and Pulmonary trunk carries blood out of the heart.
Internal structure
The human heart is four chambered. The upper two are right and left atria or auricles. The lower two are right and left ventricles. Auricles are thin walled chambered separated by inter auricular septum. There are presence of muscular ridges called musculi pectinati. Right auricle is having openings for superior and inferior venacavae to receive impure or venous blood. Left auricle is having openings for pulmonary veins to receive pure blood from lungs. The opening of inferior venacava is guarded by valve of Eustachius while the opening coronary sinus is guarded by valve of Thebesius. Right and left auricle open into respective ventricle through an auriculo ventricular apertures. These AV apertures are guarded by valves.
The sinus venosus is completely merged into right auricle. So caval veins directly open into auricles. Truncus arteriosus has split into systemic (aortic) and pulmonary trunk in mammals.
The two ventricles are separated by inter ventricular septum. The septum comes right side from the apex. Ventricles are thick walled than atria. The left ventricle is thicker than right ventricle.
Valves
Bicuspid valve is also known as mitral valve. It is situated between the left auricle and left auricle and left ventricle. It allows unidirectional flow of oxygenated blood from left atrium to left ventricle. It consists of two flaps or cusps.
Tricuspid valve is the right AV valve. It consists of three flaps or cusps. It allows impure blood to flow from right atrium to right ventricle.
Both valves are provided with tendons or chords made up of tough strands of connective tissue called chordae tendinae. The chordae tendinae arise from papillary muscle present in the wall of ventricles. Their contractions bring the tightening of chordae tendinae which in turn prevent the valves from turning inside out or from being forced upward during contraction of ventricles.
Semi lunar valves
At the base of pulmonary trunk and aortic arch, there are pulmonary semi lunar and aortic semi lunar valves. Such valve is made up of three flaps attached to inside of arterial wall. These valves allow only unidirectional flow of blood from ventricle to artery and prevent back ward flow.
Course of circulation
1. Pulmonary Circulation
It is the circulation between the heart and lungs. The impure blood(deoxygenated blood) is pumped out from the right ventricle. The pulmonary trunk takes the impure blood. The pulmonary trunk divides into two pulmonary arteries. The pulmonary arteries supply impure blood to the two lungs. In side the lungs, the impure blood is purified. After the purification, the pure blood is returned to the heart through the pulmonary veins. The pulmonary veins open into the left atrium.
2. Systemic circulation
It is the circulation of blood from heart to the whole body except the lungs. In this circulation, the pure blood is pumped from the left ventricle. The aortic arch divides into many arteries carrying pure blood to the different organs and regions of body. In the tissues, the capillary net works allow the exchange of gases and nutrients. The deoxygenated blood is then returned back through venules and veins. The impure blood is returned to right atrium through inferior and superior venacavae.
2a. Portal circulation
it is the special arrangement of veins. In this, the certain veins instead of carrying blood directly to the heart, enter into the another organ. In this case the second set of capillaries is formed. This formation of second set of capillaries is called portal system. The veins coming from the alimentary especially from the intestine and stomach contains glucose rich blood. Such blood is carried to the liver first. In the liver, the excess glucose is stored. After this the blood is carried to the heart.
2b. cororary circulation
it is the circulation of pure blood from the heart to the muscles of the heart. The coronary arteries take pure blood to the muscles of the heart and the coronary veins return the impure blood from the muscles of the heart to the heart through the superior venacava. This circulation is of utmost importance because the heart works continuously pumping the blood the different organs. For this the heart needs lot of energy. If the muscles of heart are deprived from the enough supply of pure blood, heart attack may result.
Double circulation
In one complete circulation, blood enters into the heart twice. Blood enters into the heart(left atrium) once in the form of pure blood from the lungs ( pulmonary circulation). The second time, blood enters into the heart(right atrium) in the form of impure blood from the systemic circulation. In this way, the human heart is said to be having double circulation.
Some terms
Heart beat
Heart beat consists of one contraction phase and one relaxation phase. During the contraction phase, there is maximum point(peak period) which is known as systole. During the relaxation phase also, there is minimum point which is known as diastole.
One heart beat is completed in about 0.8 second time.
Cardiac cycle
Cardiac cycle is the sequence of events during one heart beat. It consists of three phases.
• Atrial systole – the two atria contract simultaneously pumping blood into the respective ventricles. It lasts for 0.1 second.
• Ventricular systole - the two ventricles also contract pumping out the blood to the lungs and whole parts of body. It lasts for 0.3 second.
• Joint diastole - all four chambers of heart under go relaxation. At this time, both atria are filled with blood. It lasts for 0.4 second.
Stroke volume
It is the volume of blood pumped out in every heart beat. It comes to be about 70 ml of blood. It is denoted by SV.
Heart rate
It is the number of heart beats per minute time. In the normal adult, it is about 70 to 80 times. In an average, it comes to be 72 times. This is called heart rate. It is denoted by HR.
Cardiac output
It is the volume of blood pumped out in one minute time. It is given by the product of stroke volume and heart rate. It is denoted by CO
CO=SV X HR
Origin and conduction of heart beat
In the wall of right atrium, there is a special node called Sino Atrial node(SA node). It is self excitatory. It is the point of origin of heart beat. It is also called Pace maker. It is natural Pace maker. The heart cant work without it. If it is injured or damaged artificial pace maker is implanted.
Near inter atrial septum, there is Atrioventricular node (AV node). It receives the impulses in the form of wave and passes it to Purkinje’s system. This system consists of Bundle of His, purkinje fibres. With the help of this system impulses are carried to the wall of ventricle. Then both ventricles contract pumping out blood.
In the normal adult man, heart beats 70 to 80 times per minute. The average is 72 beats per minute. It is called heart rate.
Heart sounds
The first heart sound is lubb. It is produced due the sharp closing of atrioventricular valves like the bicuspid and tricuspid valves. At the beginning of ventricular systole, these valves are closed.
The second heart sound is dup. It is produced due the closing of semilunar valves at the end of the aortic arch and pulmonary aorta. It occurs at the end of ventricular systole.
Blood pressure
It is a force exerted by blood against the wall of arteries, veins and capillaries. It is called BP in short. It is of two types. Systolic blood pressure is maximum pressure during contraction. Diastolic blood pressure is minimum pressure during the relaxation. The systolic and diastolic blood pressure of a normal adult is 120/80 mm of Hg. The range of systolic blood pressure is 100 to 140. 100 is lower limit and 140 is upper limit. The range of diastolic blood pressure is 55 to 80.
Problems related to BP
Hypertension or high BP
It is the condition when the systolic and diastolic blood pressure is 150/90 or above persistently.
Causes
o Unbalanced diet, cholesterol rich food
o Smoking
o Alcohol consumption
o Stress, anxieties
o Loss of elasticity of arteries, arterosclerosis
o Vasoconstriction
Hypotension or low BP
It is the condition when the systolic and diastolic blood pressure is below the lower limit persistently.
Causes
o Unbalanced diet, less nutrient food.
o Loss of blood or less volume of blood
o Vasodilation
Arterial system
There are many arteries in the body. They distribute blood to different parts of body. All these arteries together make arterial system. This system supply pure blood to body organs and impure blood to lungs.
Pulmonary aorta arises from right ventricle. It divides to two branches. They are pulmonary arteries. These arteries supply impure blood to two lungs.
Aortic arch arises from the left ventricle. It gives one branch called innominate on the right side. It divides into right common carotid and right subclavian. On the left side, aortic arch gives left common carotid and left subclavian. The right and left common carotids ascend up through neck. In the head region, they divide into internal and external carotids. The internal carotids supply pure blood to brain. The external carotids supply to outer part of head region such jaw, tongue, face etc. The right and left subclavians enter into the fore limbs(hand). Subclavians divide into radial and ulnare arteries. They all supply pure blood to different parts of hand. There are vertebral arteries also to supply blood to neck region.
The aortic arch runs down and forms the dorsal aorta. It gives many branches. In the chest, there are intercostal arteries to supply blood to intercostal muscles. One pair of inferior phrenic arteries supply blood to the lower part of diaphragm. One coliac artery comes out from the dorsal aorta. It divides into the hepatic and leinogastric arteries. Hepatic artery supplies blood to liver. The leinogastric supplies blood to stomach and spleen. The superior mesenteric arteries divides into many branches and supply blood to duodenum, jejunum and ileum. The right and left renal arteries supply blood to the kidneys. The genital arteries supply blood to testes in male and ovaries in female.
The lumbar arteries supply blood to the wall of abdomen. The inferior mesenteric artery supplies blood to the large intestine like ascending, transverse, descending colon, pelvic colon and rectum.
Then the dorsal aorta divides into two branches called common iliacs. They enter into two legs. The right and left iliacs give small internal iliacs to supply blood to urinary bladder. The external iliacs give deep femoral which supply blood to thigh. The external iliacs run down as popliteal. These divide into anterior and posterior tibials. They supply blood to lower part of leg.
Venous system
All veins in the body together make venous system. This system is for collection of pure blood from lungs and impure blood from rest of the parts of body.
Four pulmonary veins collect pure blood form lungs and open into left atrium. Superior venacava collect blood from anterior part of body. It is made by different veins. Right and left innominate veins join to form superior venacava. Each innominate is made by right and left external and internal jugular veins collecting blood from head and brain. The right and left subclavians collect from hand. The subclavian is again made by axillary and cephalic veings. Azygous vein collects from chest region in the right side. Hemiazygous collect from left side . both open into superior venacava. Inferior venacava is made by different veins. Two short and thick hepatic veins collect blood from liver.
Two common iliac veins join to make the inferior venacava. Each iliac vein is made by internal iliac from urinary bladder, large saphenous from thigh, anterior and posterior tibial from lower part of leg.
The blood collection form stomach and intestine has different arrangement. It is called Portal system. The blood is not directly carried to the heart. It is taken to liver first. Gastric vein, duodenal vein, intestinal veins etc join to form hepatic portal vein. It enters into liver to form hepatic portal system.
Importance of hepatic portal system
o Stores excess glucose in the form of glycogen
o Converts highly poisonous ammonia into less poisonous urea
o Kills Bacteria, germs etc and protect from diseases
o Removes impurities
o Regulate body temperature etc.
Physiology of Excretion
Excretion is the removal of metabolic waste from body particularly nitrogenous waste.
Skin, lungs, liver are considered as accessory excretory organs while kidney is the most important one which forms as important part of the4 urinary system also.
Urinary system of man consists of
1. Kidneys 2. Ureters
3. Urinary bladder 4. Urethra
kidneys paired structures, chief excretory organs in man which can act as efficient
filters. Kidneys excrete nitrogenous and other metabolic wastes in the form of urine.
Ureters two ureters, one arising form each kidney. Carry urine formed in side
Kidney to urinary bladder. Each ureter is a thin muscular tube about 25
cm in length arising from hilum of each kidney. Urine moves by
peristaltic waves of its walls.
Urinary bladder present in the form of storage sac. Collects urine from both the kidneys
via ureters. Urine stored temporarily until it is released via urethra. The
volume of bladder increases as it stores much urine. It has lining of
transitional epithelium which stretches as the volume of urine increases.
Urethra small membranous tube that carries urine at intervals urinary bladder to
the exterior. There is a urethral muscular sphincter at the base of urethra
which consists of a circular band of muscle. By the contraction and
Relaxation of this muscle the flow of urine into urethra is controlled.
Sphincter keeps urethra closed except during voiding of urine.
Micturition it is act of voiding of urine. The urine is carried by peristaltic waves
down the ureter. Accumulation of urine in the bladder raises its pressure
And a continuous reflex is initiated. As the smooth muscle of bladder wall
Contract, the urethral sphincter muscle relaxes evacuating the urine. Urine
does not flow back as the ureters pass obliquely. Their terminal parts get
closed during contractions. Micturition may be initiated or delayed
Voluntarily.
Structure of kidney
A pair of kidneys located on either side of back bone in the abdominal cavity. The left kidney is positioned higher than the right one. At anterior end of kidney adrenal gland is present. Each kidney is bean shaped, about 10 cm long and 6 cm wide and weighs about 150 gm. At the concave side, there is a depression called hilum from where renal artery enters and renal vein and ureters pass out.
Internal structure
Renal cortex outer region is towards convex surface. It contains Bowman’s capsule,
glomerulus, proximal convoluted tubule, distal convoluted tubule and
collecting tubules of nephron.
Renal medulla It is region just inner to renal cortex. It contains loop of Henle and
Collecting ducts inside the renal pyramid. The conical pyramid mass
projects into renal pelvis. Urine is drained into renal pelvis through
minute openings at the apices or papillae of pyramids.
Renal pelvis large funnel shaped space behind medulla. Urine is collected and is
passed down to the ureters.
Each kidney consists of large number of filtering units called nephrons. A kidney has about 1.2 million nephrons. Each nephron is about 3 cm long, tiny, delicate and coiled
tubule which originates in the cortex region and extends into medulla region.
Structure of nephron
Nephron or uriniferous tubule is the functional unit of kidney. Each works as as independent unit and produce miniscule amount of urine. The urine collected by various ducts from all nephrons is finally poured into renal pelvis.
Nephron consists of
1. Renal corpuscle or malpighian body
a) Bowman’s capsule
b) Glomerulus
2. Proximal convoluted tubule or PCT
3. Loop of Henle
a) Descending limb of loop of Henle
b) U shaped part
c) Ascending limb of loop of Henle
4. Distal convoluted tubule or DCT
5. Collecting tubule
Renal corpuscle or malpighian body is formed by Bowman’s capsule and Glomerulus together.
Bowman’s capsule it is cup shaped hollow structure. In the hollow cup there is a network of capillaries called Glomerulus. Bowman’s capsule has inner and outer epithelial layers. Between these layers there is a cavity of Bowman’s capsule. The inner layer is closely applied to walls of Glomerulur capillaries.
Glomerulus It is network of capillaries in the hollow of Bowman’s capsule. It receives the blood through afferent arteriole which breaks up into capillary network. The blood leaves the glomerulus through efferent arteriole. The efferent arteriole is narrower and longer vessel than the afferent. The efferent arteriole breaks up into network of capillaries surrounding whole of PCT, loop of Henle and DCT. At loop of Henle, there is parallel arrangement of capillaries called vasa recta. These capillaries join and return blood to renal vein.
PCT First coiled tubule just behind renal corpuscle. It is lined by cuboidal
ciliated epithelium. It transports glomerular filtrate (GF) from Bowman’s capsule into loop of Henle.
Loop of Henle form U shaped loop. Descends down into medulla and again returns back. Descending limb is thin and long freely permeable to water. It is lined by flat epithelial Cells. Ascending limb is thicker and impermeable to water. It is lined by cuboidal epithelial cells.
DCT second coiled tubule is relatively shorter. It is permeable to water and under the control of Anti diuretic hormone (ADH)
Collecting tubule short and straight opens into collecting duct. It passes down to medulla from cortex.
Duct of Bellini many collecting ducts join to form larger duct of Bellini . it ultimately opens into renal pelvis draining all urine collected from various nephrons.
Urine formation
3 basic steps 1. Glomerular filtration or ultra filtration
2. Selective reabsorption
3. Tubular secretion
Glomerular filtration smaller diameter of efferent arteriole than that of afferent arteriole increases the blood pressure in Glomerulus. Hydrostatic pressure of about 55 mm of Hg is developed which can force out the different substances of blood into the lumen of Bowman’s capsule. This is assisted by the thin and closely applied walls of Bowman’s capsule and walls of capillaries. The hydrostatic pressure is opposed by osmotic pressure of about 30 mm of Hg and filtrate pressure of about 15 mm of Hg. The net filtration pressure is of about 10 mm of Hg.
About 125 ml of Glomerular filtrate is formed from 1200 ml of blood by both kidneys every minute. In one day 180 liters of glomerular filtrate is formed. The glomerular filtrate is composed of water, glucose, amino acids, urea, uric acid, hormones vitamins mineral salts etc. The composition of filtrate is similar to blood except in having larger molecules of protein.
Selective reabsorption of 180 liters of glomerular filtrate per day, only 1.5 liter is put out as urine. 99 % of filtrate is reabsorbed. Out of 125 ml produced every minute 124 ml is returned and 1 ml is put as urine.
Active absorption usually glucose, amino acids are returned by active absorption. It takes place against the gradient at the expense of energy.
Passive absorption normally Sodium chloride, water, urea, ammonia, ketone bodies reabsorbed by osmosis.
At the PCT, the filtrate is isotonic. From the descending limb water is returned so as the filtrate comes down it becomes hypertonic. At the ascending limb, as it impermeable to water and as salts are removed actively, the filtrate becomes hypotonic again. Much water is removed from the DCT and collecting tubule, the urine becomes hypertonic finally.
Tubular secretion If the blood in the capillaries at the DCT contains any urea, uric acid, creatinine, hippuric acid K+ , H+ , ammonia etc these can be directly put into the tubule. K+ is exchanged for Na+.
Composition of urine normally urine does not contain glucose and amino acids. It contains 95 % of water; rest of the 5 % is solute. The largest component by weight other than water is urea which account for 2 %, salts 2 % approx, 0.3 % of uric acid and traces of creatinine, creatine, ammonia etc. Urine is slightly acidic about pH 6. urochrome gives the yellowish color to the urine. The characteristic odor is due to urinod. If the urine is allowed to stand for short time also, it gives the strong smell of ammonia due to action of bacteria to change urea into ammonia.
Human body is fairly complex and performs wide range of activities. Different organs of body are located far away and may have no connection at all. Our body needs a specialized system of circulation which can connect these organs supplying nutrients, gases, hormones and carrying wastes from these organs. This system of circulation also performs the functions like regulation of things and protection. The system of circulation of some extra cellular fluid is flowing in the body. The structures associated with circulation constitute circulatory system.
Circulatory system must have these basic features
3. A pumping mechanism like heart.
4. A system of tubes through which the circulating fluid can move.
5. Presence of transporting or circulating fluid like blood or lymph.
Structure of heart
A human heart is muscular hollow pumping organ which can maintain continuous flow of blood circulation inside the body. It is roughly triangular in shape. It is about the size of a person’s fist and weighs about 300 grams. It is reddish brown in color. It is situated ventrally in the middle of thoracic cavity in between two lungs. The narrow end of the heart is slightly displaced to the left side. It can be heard towards the left side of the chest.
The heart is enclosed in a double walled membranous sac called pericardium. The inner membrane is attached to the heart. In between two membranes, there is presence of a pericardial fluid. The fluid is shock absorbing so protect heart from any shock and minor injuries. It also allows free movement to the heart.
Anterior broad part is called auricular part and posterior narrow part is called ventricular part. Towards right side of auricular part there is superior and inferior venacavae carrying impure blood from different parts of body except lungs. Towards the left side of auricular part, the pulmonary veins carry pure blood from lungs. The auricular part receives blood. The lower ventricular part sends out blood. The arch of Aorta and Pulmonary trunk carries blood out of the heart.
Internal structure
The human heart is four chambered. The upper two are right and left atria or auricles. The lower two are right and left ventricles. Auricles are thin walled chambered separated by inter auricular septum. There are presence of muscular ridges called musculi pectinati. Right auricle is having openings for superior and inferior venacavae to receive impure or venous blood. Left auricle is having openings for pulmonary veins to receive pure blood from lungs. The opening of inferior venacava is guarded by valve of Eustachius while the opening coronary sinus is guarded by valve of Thebesius. Right and left auricle open into respective ventricle through an auriculo ventricular apertures. These AV apertures are guarded by valves.
The sinus venosus is completely merged into right auricle. So caval veins directly open into auricles. Truncus arteriosus has split into systemic (aortic) and pulmonary trunk in mammals.
The two ventricles are separated by inter ventricular septum. The septum comes right side from the apex. Ventricles are thick walled than atria. The left ventricle is thicker than right ventricle.
Valves
Bicuspid valve is also known as mitral valve. It is situated between the left auricle and left auricle and left ventricle. It allows unidirectional flow of oxygenated blood from left atrium to left ventricle. It consists of two flaps or cusps.
Tricuspid valve is the right AV valve. It consists of three flaps or cusps. It allows impure blood to flow from right atrium to right ventricle.
Both valves are provided with tendons or chords made up of tough strands of connective tissue called chordae tendinae. The chordae tendinae arise from papillary muscle present in the wall of ventricles. Their contractions bring the tightening of chordae tendinae which in turn prevent the valves from turning inside out or from being forced upward during contraction of ventricles.
Semi lunar valves
At the base of pulmonary trunk and aortic arch, there are pulmonary semi lunar and aortic semi lunar valves. Such valve is made up of three flaps attached to inside of arterial wall. These valves allow only unidirectional flow of blood from ventricle to artery and prevent back ward flow.
Course of circulation
1. Pulmonary Circulation
It is the circulation between the heart and lungs. The impure blood(deoxygenated blood) is pumped out from the right ventricle. The pulmonary trunk takes the impure blood. The pulmonary trunk divides into two pulmonary arteries. The pulmonary arteries supply impure blood to the two lungs. In side the lungs, the impure blood is purified. After the purification, the pure blood is returned to the heart through the pulmonary veins. The pulmonary veins open into the left atrium.
2. Systemic circulation
It is the circulation of blood from heart to the whole body except the lungs. In this circulation, the pure blood is pumped from the left ventricle. The aortic arch divides into many arteries carrying pure blood to the different organs and regions of body. In the tissues, the capillary net works allow the exchange of gases and nutrients. The deoxygenated blood is then returned back through venules and veins. The impure blood is returned to right atrium through inferior and superior venacavae.
2a. Portal circulation
it is the special arrangement of veins. In this, the certain veins instead of carrying blood directly to the heart, enter into the another organ. In this case the second set of capillaries is formed. This formation of second set of capillaries is called portal system. The veins coming from the alimentary especially from the intestine and stomach contains glucose rich blood. Such blood is carried to the liver first. In the liver, the excess glucose is stored. After this the blood is carried to the heart.
2b. cororary circulation
it is the circulation of pure blood from the heart to the muscles of the heart. The coronary arteries take pure blood to the muscles of the heart and the coronary veins return the impure blood from the muscles of the heart to the heart through the superior venacava. This circulation is of utmost importance because the heart works continuously pumping the blood the different organs. For this the heart needs lot of energy. If the muscles of heart are deprived from the enough supply of pure blood, heart attack may result.
Double circulation
In one complete circulation, blood enters into the heart twice. Blood enters into the heart(left atrium) once in the form of pure blood from the lungs ( pulmonary circulation). The second time, blood enters into the heart(right atrium) in the form of impure blood from the systemic circulation. In this way, the human heart is said to be having double circulation.
Some terms
Heart beat
Heart beat consists of one contraction phase and one relaxation phase. During the contraction phase, there is maximum point(peak period) which is known as systole. During the relaxation phase also, there is minimum point which is known as diastole.
One heart beat is completed in about 0.8 second time.
Cardiac cycle
Cardiac cycle is the sequence of events during one heart beat. It consists of three phases.
• Atrial systole – the two atria contract simultaneously pumping blood into the respective ventricles. It lasts for 0.1 second.
• Ventricular systole - the two ventricles also contract pumping out the blood to the lungs and whole parts of body. It lasts for 0.3 second.
• Joint diastole - all four chambers of heart under go relaxation. At this time, both atria are filled with blood. It lasts for 0.4 second.
Stroke volume
It is the volume of blood pumped out in every heart beat. It comes to be about 70 ml of blood. It is denoted by SV.
Heart rate
It is the number of heart beats per minute time. In the normal adult, it is about 70 to 80 times. In an average, it comes to be 72 times. This is called heart rate. It is denoted by HR.
Cardiac output
It is the volume of blood pumped out in one minute time. It is given by the product of stroke volume and heart rate. It is denoted by CO
CO=SV X HR
Origin and conduction of heart beat
In the wall of right atrium, there is a special node called Sino Atrial node(SA node). It is self excitatory. It is the point of origin of heart beat. It is also called Pace maker. It is natural Pace maker. The heart cant work without it. If it is injured or damaged artificial pace maker is implanted.
Near inter atrial septum, there is Atrioventricular node (AV node). It receives the impulses in the form of wave and passes it to Purkinje’s system. This system consists of Bundle of His, purkinje fibres. With the help of this system impulses are carried to the wall of ventricle. Then both ventricles contract pumping out blood.
In the normal adult man, heart beats 70 to 80 times per minute. The average is 72 beats per minute. It is called heart rate.
Heart sounds
The first heart sound is lubb. It is produced due the sharp closing of atrioventricular valves like the bicuspid and tricuspid valves. At the beginning of ventricular systole, these valves are closed.
The second heart sound is dup. It is produced due the closing of semilunar valves at the end of the aortic arch and pulmonary aorta. It occurs at the end of ventricular systole.
Blood pressure
It is a force exerted by blood against the wall of arteries, veins and capillaries. It is called BP in short. It is of two types. Systolic blood pressure is maximum pressure during contraction. Diastolic blood pressure is minimum pressure during the relaxation. The systolic and diastolic blood pressure of a normal adult is 120/80 mm of Hg. The range of systolic blood pressure is 100 to 140. 100 is lower limit and 140 is upper limit. The range of diastolic blood pressure is 55 to 80.
Problems related to BP
Hypertension or high BP
It is the condition when the systolic and diastolic blood pressure is 150/90 or above persistently.
Causes
o Unbalanced diet, cholesterol rich food
o Smoking
o Alcohol consumption
o Stress, anxieties
o Loss of elasticity of arteries, arterosclerosis
o Vasoconstriction
Hypotension or low BP
It is the condition when the systolic and diastolic blood pressure is below the lower limit persistently.
Causes
o Unbalanced diet, less nutrient food.
o Loss of blood or less volume of blood
o Vasodilation
Arterial system
There are many arteries in the body. They distribute blood to different parts of body. All these arteries together make arterial system. This system supply pure blood to body organs and impure blood to lungs.
Pulmonary aorta arises from right ventricle. It divides to two branches. They are pulmonary arteries. These arteries supply impure blood to two lungs.
Aortic arch arises from the left ventricle. It gives one branch called innominate on the right side. It divides into right common carotid and right subclavian. On the left side, aortic arch gives left common carotid and left subclavian. The right and left common carotids ascend up through neck. In the head region, they divide into internal and external carotids. The internal carotids supply pure blood to brain. The external carotids supply to outer part of head region such jaw, tongue, face etc. The right and left subclavians enter into the fore limbs(hand). Subclavians divide into radial and ulnare arteries. They all supply pure blood to different parts of hand. There are vertebral arteries also to supply blood to neck region.
The aortic arch runs down and forms the dorsal aorta. It gives many branches. In the chest, there are intercostal arteries to supply blood to intercostal muscles. One pair of inferior phrenic arteries supply blood to the lower part of diaphragm. One coliac artery comes out from the dorsal aorta. It divides into the hepatic and leinogastric arteries. Hepatic artery supplies blood to liver. The leinogastric supplies blood to stomach and spleen. The superior mesenteric arteries divides into many branches and supply blood to duodenum, jejunum and ileum. The right and left renal arteries supply blood to the kidneys. The genital arteries supply blood to testes in male and ovaries in female.
The lumbar arteries supply blood to the wall of abdomen. The inferior mesenteric artery supplies blood to the large intestine like ascending, transverse, descending colon, pelvic colon and rectum.
Then the dorsal aorta divides into two branches called common iliacs. They enter into two legs. The right and left iliacs give small internal iliacs to supply blood to urinary bladder. The external iliacs give deep femoral which supply blood to thigh. The external iliacs run down as popliteal. These divide into anterior and posterior tibials. They supply blood to lower part of leg.
Venous system
All veins in the body together make venous system. This system is for collection of pure blood from lungs and impure blood from rest of the parts of body.
Four pulmonary veins collect pure blood form lungs and open into left atrium. Superior venacava collect blood from anterior part of body. It is made by different veins. Right and left innominate veins join to form superior venacava. Each innominate is made by right and left external and internal jugular veins collecting blood from head and brain. The right and left subclavians collect from hand. The subclavian is again made by axillary and cephalic veings. Azygous vein collects from chest region in the right side. Hemiazygous collect from left side . both open into superior venacava. Inferior venacava is made by different veins. Two short and thick hepatic veins collect blood from liver.
Two common iliac veins join to make the inferior venacava. Each iliac vein is made by internal iliac from urinary bladder, large saphenous from thigh, anterior and posterior tibial from lower part of leg.
The blood collection form stomach and intestine has different arrangement. It is called Portal system. The blood is not directly carried to the heart. It is taken to liver first. Gastric vein, duodenal vein, intestinal veins etc join to form hepatic portal vein. It enters into liver to form hepatic portal system.
Importance of hepatic portal system
o Stores excess glucose in the form of glycogen
o Converts highly poisonous ammonia into less poisonous urea
o Kills Bacteria, germs etc and protect from diseases
o Removes impurities
o Regulate body temperature etc.
Physiology of Excretion
Excretion is the removal of metabolic waste from body particularly nitrogenous waste.
Skin, lungs, liver are considered as accessory excretory organs while kidney is the most important one which forms as important part of the4 urinary system also.
Urinary system of man consists of
1. Kidneys 2. Ureters
3. Urinary bladder 4. Urethra
kidneys paired structures, chief excretory organs in man which can act as efficient
filters. Kidneys excrete nitrogenous and other metabolic wastes in the form of urine.
Ureters two ureters, one arising form each kidney. Carry urine formed in side
Kidney to urinary bladder. Each ureter is a thin muscular tube about 25
cm in length arising from hilum of each kidney. Urine moves by
peristaltic waves of its walls.
Urinary bladder present in the form of storage sac. Collects urine from both the kidneys
via ureters. Urine stored temporarily until it is released via urethra. The
volume of bladder increases as it stores much urine. It has lining of
transitional epithelium which stretches as the volume of urine increases.
Urethra small membranous tube that carries urine at intervals urinary bladder to
the exterior. There is a urethral muscular sphincter at the base of urethra
which consists of a circular band of muscle. By the contraction and
Relaxation of this muscle the flow of urine into urethra is controlled.
Sphincter keeps urethra closed except during voiding of urine.
Micturition it is act of voiding of urine. The urine is carried by peristaltic waves
down the ureter. Accumulation of urine in the bladder raises its pressure
And a continuous reflex is initiated. As the smooth muscle of bladder wall
Contract, the urethral sphincter muscle relaxes evacuating the urine. Urine
does not flow back as the ureters pass obliquely. Their terminal parts get
closed during contractions. Micturition may be initiated or delayed
Voluntarily.
Structure of kidney
A pair of kidneys located on either side of back bone in the abdominal cavity. The left kidney is positioned higher than the right one. At anterior end of kidney adrenal gland is present. Each kidney is bean shaped, about 10 cm long and 6 cm wide and weighs about 150 gm. At the concave side, there is a depression called hilum from where renal artery enters and renal vein and ureters pass out.
Internal structure
Renal cortex outer region is towards convex surface. It contains Bowman’s capsule,
glomerulus, proximal convoluted tubule, distal convoluted tubule and
collecting tubules of nephron.
Renal medulla It is region just inner to renal cortex. It contains loop of Henle and
Collecting ducts inside the renal pyramid. The conical pyramid mass
projects into renal pelvis. Urine is drained into renal pelvis through
minute openings at the apices or papillae of pyramids.
Renal pelvis large funnel shaped space behind medulla. Urine is collected and is
passed down to the ureters.
Each kidney consists of large number of filtering units called nephrons. A kidney has about 1.2 million nephrons. Each nephron is about 3 cm long, tiny, delicate and coiled
tubule which originates in the cortex region and extends into medulla region.
Structure of nephron
Nephron or uriniferous tubule is the functional unit of kidney. Each works as as independent unit and produce miniscule amount of urine. The urine collected by various ducts from all nephrons is finally poured into renal pelvis.
Nephron consists of
1. Renal corpuscle or malpighian body
a) Bowman’s capsule
b) Glomerulus
2. Proximal convoluted tubule or PCT
3. Loop of Henle
a) Descending limb of loop of Henle
b) U shaped part
c) Ascending limb of loop of Henle
4. Distal convoluted tubule or DCT
5. Collecting tubule
Renal corpuscle or malpighian body is formed by Bowman’s capsule and Glomerulus together.
Bowman’s capsule it is cup shaped hollow structure. In the hollow cup there is a network of capillaries called Glomerulus. Bowman’s capsule has inner and outer epithelial layers. Between these layers there is a cavity of Bowman’s capsule. The inner layer is closely applied to walls of Glomerulur capillaries.
Glomerulus It is network of capillaries in the hollow of Bowman’s capsule. It receives the blood through afferent arteriole which breaks up into capillary network. The blood leaves the glomerulus through efferent arteriole. The efferent arteriole is narrower and longer vessel than the afferent. The efferent arteriole breaks up into network of capillaries surrounding whole of PCT, loop of Henle and DCT. At loop of Henle, there is parallel arrangement of capillaries called vasa recta. These capillaries join and return blood to renal vein.
PCT First coiled tubule just behind renal corpuscle. It is lined by cuboidal
ciliated epithelium. It transports glomerular filtrate (GF) from Bowman’s capsule into loop of Henle.
Loop of Henle form U shaped loop. Descends down into medulla and again returns back. Descending limb is thin and long freely permeable to water. It is lined by flat epithelial Cells. Ascending limb is thicker and impermeable to water. It is lined by cuboidal epithelial cells.
DCT second coiled tubule is relatively shorter. It is permeable to water and under the control of Anti diuretic hormone (ADH)
Collecting tubule short and straight opens into collecting duct. It passes down to medulla from cortex.
Duct of Bellini many collecting ducts join to form larger duct of Bellini . it ultimately opens into renal pelvis draining all urine collected from various nephrons.
Urine formation
3 basic steps 1. Glomerular filtration or ultra filtration
2. Selective reabsorption
3. Tubular secretion
Glomerular filtration smaller diameter of efferent arteriole than that of afferent arteriole increases the blood pressure in Glomerulus. Hydrostatic pressure of about 55 mm of Hg is developed which can force out the different substances of blood into the lumen of Bowman’s capsule. This is assisted by the thin and closely applied walls of Bowman’s capsule and walls of capillaries. The hydrostatic pressure is opposed by osmotic pressure of about 30 mm of Hg and filtrate pressure of about 15 mm of Hg. The net filtration pressure is of about 10 mm of Hg.
About 125 ml of Glomerular filtrate is formed from 1200 ml of blood by both kidneys every minute. In one day 180 liters of glomerular filtrate is formed. The glomerular filtrate is composed of water, glucose, amino acids, urea, uric acid, hormones vitamins mineral salts etc. The composition of filtrate is similar to blood except in having larger molecules of protein.
Selective reabsorption of 180 liters of glomerular filtrate per day, only 1.5 liter is put out as urine. 99 % of filtrate is reabsorbed. Out of 125 ml produced every minute 124 ml is returned and 1 ml is put as urine.
Active absorption usually glucose, amino acids are returned by active absorption. It takes place against the gradient at the expense of energy.
Passive absorption normally Sodium chloride, water, urea, ammonia, ketone bodies reabsorbed by osmosis.
At the PCT, the filtrate is isotonic. From the descending limb water is returned so as the filtrate comes down it becomes hypertonic. At the ascending limb, as it impermeable to water and as salts are removed actively, the filtrate becomes hypotonic again. Much water is removed from the DCT and collecting tubule, the urine becomes hypertonic finally.
Tubular secretion If the blood in the capillaries at the DCT contains any urea, uric acid, creatinine, hippuric acid K+ , H+ , ammonia etc these can be directly put into the tubule. K+ is exchanged for Na+.
Composition of urine normally urine does not contain glucose and amino acids. It contains 95 % of water; rest of the 5 % is solute. The largest component by weight other than water is urea which account for 2 %, salts 2 % approx, 0.3 % of uric acid and traces of creatinine, creatine, ammonia etc. Urine is slightly acidic about pH 6. urochrome gives the yellowish color to the urine. The characteristic odor is due to urinod. If the urine is allowed to stand for short time also, it gives the strong smell of ammonia due to action of bacteria to change urea into ammonia.
for Grade XII
Respiration
Respiration can be defined as a biochemical process in which organic compounds are oxidized to liberate energy. Energy is released in a step wise process. The energy is trapped in a chemical bonds of adenosine triphosphate ATP molecules. ATP is instant sources as universal energy carriers. It is a catabolic process.
Types
1. Aerobic
It occurs in all higher forms (organisms) in this type Oxygen is necessary.
C6H12O6 + 6O2 -------- 6CO2 + 6H2O + 2880 K joule .
2. Anaerobic respiration
C6H12O6 ----------- C2H5OH(ethyl alcohol) + CO2 + 210 K joule example yeast
C6H12O6 ----------- C3H6O¬3 (lactic acid)+ energy example intestinal worms
It occurs in Yeast cells, Bacteria etc. Oxygen is not necessary. Glucose molecules are changed into ethyl alcohol and Carbon dioxide. This process is referred to fermentation.
Pulmonary respiration
All mammals whether aquatic like Dolphin, Whales etc or terrestrial have lungs as respiratory organ. The respiration by lungs is called pulmonary respiration. In man, respiratory organs are lungs and respiratory tracts which include nostrils, nasal chamber, internal nostril, nasopharynx, larynx, trachea and bronchi etc.
Nostrils are openings of nasal chamber. Nasal chambers are lined with mucous membranes which are ciliated epithelium. Nasal chambers are paired structures separated by nasal septum. Each nasal chamber has 3 parts
1. vestibular part - it is the anterior part with hairy skin which acts as filter preventing the entry of dust particles.
2. respiratory part - it is the middle part lined by glandular and vascular respiratory epithelium. It acts as air conditioner and brings the inspired air at body temperature.
3. olfactory part - it is posterior part and lined by highly sensory olfactory epithelium( Schneiderian membrane). It helps in smelling.
Functions _ filtration of air by hairs, prevent dust from entering.
_ moisten the dry air by mucous.
_ mucous traps dirt.
_ air warmed by capillary network.
_ detect smell.
Internal nostril open into nasopharynx. Little below this, is the laryngopharynx. There is presence of aperture called glottis. Glottis can be closed by leaf like cartilage epiglottis during the swallowing of food. Epiglottis prevents the entry of food into glottis. Glottis opens into larynx. Larynx is called voice box. It is cartilaginous structure. It is more developed in males than in females. It is also called Adam’s apple. It is supported by four cartilages, one cricoid, one thyroid and two arytenoids. It is lined by stratified columnar ciliated epithelium. The cilia of which beat out ward and eject the unwanted substances. There are presence of 2 pairs of vocal cords. The true pair of vocal cords set into vibrations when air is forced to go out from lungs. The vibrations produce the sound. The pitch of sound is controlled by muscles. The larynx opens into trachea.
Trachea runs through neck in front of oesophagus and extend into the thoracic cavity. It is the wind pipe about 12 cm long. It is provided with 16 to 20 dorsally incomplete c-shaped tracheal rings of cartilage. Cartilagenous rings prevents trachea from collapsing. Trachea divides into 2 primary bronchi. These are also provided with cartilaginous rings. Each primary bronchus enters into lung of its side. The right bronchus divides into 3 branches and left into 2 branches.
After entering into the lungs, primary bronchioles divide into large no. of bronchial tubes called secondary bronchioles. The secondary bronchioles further subdivides into tertiary bronchioles and then into alveolar ducts. The alveolar duct ends in alveolar sac containing 6 to 8 pocket like outgrowths called air sacs. The air sacs are about 0.1 mm in diameter. These branches make the bronchial tree.
Respiratory organs
There is a pair of spongy conical hollow bags enclosed in pleural cavities called lungs. The plural cavities are lined by tough, flexible and transparent membranes called pleura. The plura is double walled. The outer membrane is parietal and inner membrane is visceral membrane. These membranes protect lungs and stop leaking of air into thoracic cavity. The fluid secreted by pleura reduces the friction during breathing movement. The lungs are capable of great expansion. They are inflated when filled with air. These are found in either side of heart. The right lung has three lobes and left lung has two lobes. The three lobes of right lung are right superior, right inferior and middle lobe. The two lobes of left lung are left superior and left inferior. The left lung has cardiac notch at its anteromedian border to accommodate the heart. There are about 750 millions of alveoli. These large no. of alveoli provide about 100 sq meter of surface. It is about 50 times of skin surface(1.6 sq m). Alveoli are extremely thin walled and vascular structure surrounded by capillary of network. These are the site for gases exchange.
Mechanism of breathing
Breathing is simply taking in of fresh air from atmosphere and giving out of used air from lungs. Breathing renews constantly the air present in the lungs. It is accomplished through changes in the volume and air pressure of the thoracic cavity. Change in volume and air pressure is carried out by movement of ribs, internal and external intercostals muscles, diaphragm and abdominal muscles. Breathing can be divided into inhalation and exhalation.
Difference between inhalation and exhalation
Inhalation exhalation
1. Taking in of atmospheric air 1. giving out of air from lungs.
2. contraction of external intercostal 2. relaxation of external intercostals
muscle or inspiratory muscle and muscle and contraction of intercostal
relaxation of internal intercostals muscle. muscle.
3. rib cage moves forward and outward 3. rib cage moves downward and inward.
4. diaphragm contracts and becomes 4. diaphragm relaxes and become dome
flattened. shaped.
5. increase in the volume of thoracic cavity. 5. decrease in volume of thoracic cavity.
6. decease in air pressure(below atmos- 6. increase in the air pressure.
pheric pressure.
7. rushing in of air through nostril into 7. expulsion of air from lungs into atmos-
alveolar sacs causing inflation of lung. phere causing deflation of lungs.
One breath includes one inspiration or inhalation and one expiration of exhalation. The respiratory rate is the no. of breaths taken per minute. At rest, for a normal person, it is equal to 12 to 14 breaths per minute. The pulmonary air volume during breathing is measured by an apparatus called Spirometer.
Tidal volume(TV) - volume of air that is breathed in or out during effortless normal breathing. It is about 500 ml.
Inspiratory reserve volume(IRV) - it is an extra volume of air over and above the tidal volume that can be taken in during a deep breath. It is about 1500 to 2500 ml.
Expiratory reserve volume(ERV) - after a normal expiration one can still expel a large volume of air. It is known as ERV. It is about 1500 ml.
Vital capacity(VC) - it is total volume of air expired after a maximum inspiration. It is about 3.5 to 4.5 L for normal adult and about 6 L for athlete.
Total lung capacity(TLC) - it refers to amount of air present in the lung after maximum inhalation. It is equivalent to 5 to 5.5 L
Residual volume)RV) - it is the amount of air left in the lungs even after maximum expiratory effort. It can never be forced out of lungs. It is about 1500 ml.
Dead space - it is amount of air that is present in the respiratory tubes where gases exchange does not occur. With each expiration it is expelled out without undergoing any change in O2 and CO2 concentration. It is equivalent to about 150 ml. Out of tidal volume of 500 ml, 150 ml remains in the respiratory tubes as dead space and the only the rest of 350 ml is present in alveolar sacs in the lungs for exchange of gases.
Respiratory Quotient - it is the ratio of volume of CO2 produced and volume of O2 used during the respiration. It is RQ in short. For hexose sugar,
RQ = volume of CO2/volume of O2
= 6/6
= 1
for fat it is about 0.71 and for protein it is about 0.80
for mixed food it is about 0.85
RQ can show the nature of food one has taken.
Physiology of respiration
Physiology of respiration can be studied under following headings.
1. external respiration
2. transportation of O2 by blood
3. internal respiration
4. transportation of CO2 by blood.
External respiration - it is uptake of O2 and release of CO2. It takes place in the lungs called breathing.
Transport of O2 by blood - RBC of blood contain haemoglobin as respiratory pigment. Human blood contains nearly 150 gram of Hb per 100 ml. haemoglobin readily combines with and dissociates to form free Oxygen.
Hb + O2 == HbO2
Oxyhaemoglobin is unstable compound and thus can dissociate quickly.
The quantity of O2 combining with Hb depends upon pressure of Oxygen. The graph in which percentage of saturation of blood is plotted against PO2 is called Oxygen dissociaton curve. It is S shaped. It indicates that blood has high affinity for O2.
In man, arterial blood has PO2 of about 95 mm Hg and Hb is about 95 % saturated. In venous blood, PO2 is about 40 mm Hg and about 70 % haemoglobin is saturated with O2. The Oxygen and CO2 transport is closely associated. Increase in conc. of CO2 decreases the amount of O2 that can be carried in the blood at a given partial pressure of O2. This is known as Bohr’s effect. The graph shows that the increase in the PCO2 lowers the curve.
Internal respiration - it is tissue respiration. Digested food is oxidized to liberate energy.
Transport of CO2 - CO2 is product of respiration. CO2 is poisonous. It should be removed quickly. It takes place by following way.
1. By plasma in the form of carbonic acid - CO2 dissolve in water of blood plasma to form carbonic acid, about 7 % of total CO2 s carried in this way.
2. In the form of bicarbonates of Na and K - CO2 enters into the RBC to dissolve into water. It is catalysed by carbonic anhydrase enzyme. H2CO3 ionises to form bicarbonate and hydrogen. The bicarbonate ions combine with Potassium ion to form Potassium bicarbonate. Upon saturation, Potassium bicarbonate ionizes into Potassium and bicarbonate ion, These ions being at higher conc. within red cells, come out into plasma and combine with available Na ion to form Sodium bicarbonates. The loss of bicarbonate ions is balanced by chloride ions diffusing into RBC from plasma . the exchange of Cl and HCO3 between plasma and RBC is known as Chloride shift or Hamberger’s phenomenon. In the lungs, these reactions are reversed. The exchange of Cl and HCO3 is reversed. H2CO3 is formed again which break down into water and CO2. CO2 in exhaled. In this way about 70 % of CO2 is transported.
3. By RBC in the form of carbamino compounds - amino acid present in RBC get oxidized to release amino group and carboxyl group. Carbon dioxide combines with amino group to form carbamino compounds. About 23 % is transported in this form.
Respiration can be defined as a biochemical process in which organic compounds are oxidized to liberate energy. Energy is released in a step wise process. The energy is trapped in a chemical bonds of adenosine triphosphate ATP molecules. ATP is instant sources as universal energy carriers. It is a catabolic process.
Types
1. Aerobic
It occurs in all higher forms (organisms) in this type Oxygen is necessary.
C6H12O6 + 6O2 -------- 6CO2 + 6H2O + 2880 K joule .
2. Anaerobic respiration
C6H12O6 ----------- C2H5OH(ethyl alcohol) + CO2 + 210 K joule example yeast
C6H12O6 ----------- C3H6O¬3 (lactic acid)+ energy example intestinal worms
It occurs in Yeast cells, Bacteria etc. Oxygen is not necessary. Glucose molecules are changed into ethyl alcohol and Carbon dioxide. This process is referred to fermentation.
Pulmonary respiration
All mammals whether aquatic like Dolphin, Whales etc or terrestrial have lungs as respiratory organ. The respiration by lungs is called pulmonary respiration. In man, respiratory organs are lungs and respiratory tracts which include nostrils, nasal chamber, internal nostril, nasopharynx, larynx, trachea and bronchi etc.
Nostrils are openings of nasal chamber. Nasal chambers are lined with mucous membranes which are ciliated epithelium. Nasal chambers are paired structures separated by nasal septum. Each nasal chamber has 3 parts
1. vestibular part - it is the anterior part with hairy skin which acts as filter preventing the entry of dust particles.
2. respiratory part - it is the middle part lined by glandular and vascular respiratory epithelium. It acts as air conditioner and brings the inspired air at body temperature.
3. olfactory part - it is posterior part and lined by highly sensory olfactory epithelium( Schneiderian membrane). It helps in smelling.
Functions _ filtration of air by hairs, prevent dust from entering.
_ moisten the dry air by mucous.
_ mucous traps dirt.
_ air warmed by capillary network.
_ detect smell.
Internal nostril open into nasopharynx. Little below this, is the laryngopharynx. There is presence of aperture called glottis. Glottis can be closed by leaf like cartilage epiglottis during the swallowing of food. Epiglottis prevents the entry of food into glottis. Glottis opens into larynx. Larynx is called voice box. It is cartilaginous structure. It is more developed in males than in females. It is also called Adam’s apple. It is supported by four cartilages, one cricoid, one thyroid and two arytenoids. It is lined by stratified columnar ciliated epithelium. The cilia of which beat out ward and eject the unwanted substances. There are presence of 2 pairs of vocal cords. The true pair of vocal cords set into vibrations when air is forced to go out from lungs. The vibrations produce the sound. The pitch of sound is controlled by muscles. The larynx opens into trachea.
Trachea runs through neck in front of oesophagus and extend into the thoracic cavity. It is the wind pipe about 12 cm long. It is provided with 16 to 20 dorsally incomplete c-shaped tracheal rings of cartilage. Cartilagenous rings prevents trachea from collapsing. Trachea divides into 2 primary bronchi. These are also provided with cartilaginous rings. Each primary bronchus enters into lung of its side. The right bronchus divides into 3 branches and left into 2 branches.
After entering into the lungs, primary bronchioles divide into large no. of bronchial tubes called secondary bronchioles. The secondary bronchioles further subdivides into tertiary bronchioles and then into alveolar ducts. The alveolar duct ends in alveolar sac containing 6 to 8 pocket like outgrowths called air sacs. The air sacs are about 0.1 mm in diameter. These branches make the bronchial tree.
Respiratory organs
There is a pair of spongy conical hollow bags enclosed in pleural cavities called lungs. The plural cavities are lined by tough, flexible and transparent membranes called pleura. The plura is double walled. The outer membrane is parietal and inner membrane is visceral membrane. These membranes protect lungs and stop leaking of air into thoracic cavity. The fluid secreted by pleura reduces the friction during breathing movement. The lungs are capable of great expansion. They are inflated when filled with air. These are found in either side of heart. The right lung has three lobes and left lung has two lobes. The three lobes of right lung are right superior, right inferior and middle lobe. The two lobes of left lung are left superior and left inferior. The left lung has cardiac notch at its anteromedian border to accommodate the heart. There are about 750 millions of alveoli. These large no. of alveoli provide about 100 sq meter of surface. It is about 50 times of skin surface(1.6 sq m). Alveoli are extremely thin walled and vascular structure surrounded by capillary of network. These are the site for gases exchange.
Mechanism of breathing
Breathing is simply taking in of fresh air from atmosphere and giving out of used air from lungs. Breathing renews constantly the air present in the lungs. It is accomplished through changes in the volume and air pressure of the thoracic cavity. Change in volume and air pressure is carried out by movement of ribs, internal and external intercostals muscles, diaphragm and abdominal muscles. Breathing can be divided into inhalation and exhalation.
Difference between inhalation and exhalation
Inhalation exhalation
1. Taking in of atmospheric air 1. giving out of air from lungs.
2. contraction of external intercostal 2. relaxation of external intercostals
muscle or inspiratory muscle and muscle and contraction of intercostal
relaxation of internal intercostals muscle. muscle.
3. rib cage moves forward and outward 3. rib cage moves downward and inward.
4. diaphragm contracts and becomes 4. diaphragm relaxes and become dome
flattened. shaped.
5. increase in the volume of thoracic cavity. 5. decrease in volume of thoracic cavity.
6. decease in air pressure(below atmos- 6. increase in the air pressure.
pheric pressure.
7. rushing in of air through nostril into 7. expulsion of air from lungs into atmos-
alveolar sacs causing inflation of lung. phere causing deflation of lungs.
One breath includes one inspiration or inhalation and one expiration of exhalation. The respiratory rate is the no. of breaths taken per minute. At rest, for a normal person, it is equal to 12 to 14 breaths per minute. The pulmonary air volume during breathing is measured by an apparatus called Spirometer.
Tidal volume(TV) - volume of air that is breathed in or out during effortless normal breathing. It is about 500 ml.
Inspiratory reserve volume(IRV) - it is an extra volume of air over and above the tidal volume that can be taken in during a deep breath. It is about 1500 to 2500 ml.
Expiratory reserve volume(ERV) - after a normal expiration one can still expel a large volume of air. It is known as ERV. It is about 1500 ml.
Vital capacity(VC) - it is total volume of air expired after a maximum inspiration. It is about 3.5 to 4.5 L for normal adult and about 6 L for athlete.
Total lung capacity(TLC) - it refers to amount of air present in the lung after maximum inhalation. It is equivalent to 5 to 5.5 L
Residual volume)RV) - it is the amount of air left in the lungs even after maximum expiratory effort. It can never be forced out of lungs. It is about 1500 ml.
Dead space - it is amount of air that is present in the respiratory tubes where gases exchange does not occur. With each expiration it is expelled out without undergoing any change in O2 and CO2 concentration. It is equivalent to about 150 ml. Out of tidal volume of 500 ml, 150 ml remains in the respiratory tubes as dead space and the only the rest of 350 ml is present in alveolar sacs in the lungs for exchange of gases.
Respiratory Quotient - it is the ratio of volume of CO2 produced and volume of O2 used during the respiration. It is RQ in short. For hexose sugar,
RQ = volume of CO2/volume of O2
= 6/6
= 1
for fat it is about 0.71 and for protein it is about 0.80
for mixed food it is about 0.85
RQ can show the nature of food one has taken.
Physiology of respiration
Physiology of respiration can be studied under following headings.
1. external respiration
2. transportation of O2 by blood
3. internal respiration
4. transportation of CO2 by blood.
External respiration - it is uptake of O2 and release of CO2. It takes place in the lungs called breathing.
Transport of O2 by blood - RBC of blood contain haemoglobin as respiratory pigment. Human blood contains nearly 150 gram of Hb per 100 ml. haemoglobin readily combines with and dissociates to form free Oxygen.
Hb + O2 == HbO2
Oxyhaemoglobin is unstable compound and thus can dissociate quickly.
The quantity of O2 combining with Hb depends upon pressure of Oxygen. The graph in which percentage of saturation of blood is plotted against PO2 is called Oxygen dissociaton curve. It is S shaped. It indicates that blood has high affinity for O2.
In man, arterial blood has PO2 of about 95 mm Hg and Hb is about 95 % saturated. In venous blood, PO2 is about 40 mm Hg and about 70 % haemoglobin is saturated with O2. The Oxygen and CO2 transport is closely associated. Increase in conc. of CO2 decreases the amount of O2 that can be carried in the blood at a given partial pressure of O2. This is known as Bohr’s effect. The graph shows that the increase in the PCO2 lowers the curve.
Internal respiration - it is tissue respiration. Digested food is oxidized to liberate energy.
Transport of CO2 - CO2 is product of respiration. CO2 is poisonous. It should be removed quickly. It takes place by following way.
1. By plasma in the form of carbonic acid - CO2 dissolve in water of blood plasma to form carbonic acid, about 7 % of total CO2 s carried in this way.
2. In the form of bicarbonates of Na and K - CO2 enters into the RBC to dissolve into water. It is catalysed by carbonic anhydrase enzyme. H2CO3 ionises to form bicarbonate and hydrogen. The bicarbonate ions combine with Potassium ion to form Potassium bicarbonate. Upon saturation, Potassium bicarbonate ionizes into Potassium and bicarbonate ion, These ions being at higher conc. within red cells, come out into plasma and combine with available Na ion to form Sodium bicarbonates. The loss of bicarbonate ions is balanced by chloride ions diffusing into RBC from plasma . the exchange of Cl and HCO3 between plasma and RBC is known as Chloride shift or Hamberger’s phenomenon. In the lungs, these reactions are reversed. The exchange of Cl and HCO3 is reversed. H2CO3 is formed again which break down into water and CO2. CO2 in exhaled. In this way about 70 % of CO2 is transported.
3. By RBC in the form of carbamino compounds - amino acid present in RBC get oxidized to release amino group and carboxyl group. Carbon dioxide combines with amino group to form carbamino compounds. About 23 % is transported in this form.
for grade XII
digestive system
Human beings are heterotrophic. It means they can not manufacture their food and depend upon plants or other animals. They have holozoic type of nutrition. The nutrition is animal like. Human beings are omnivorous in nature.
The digestive system consists of alimentary canal and digestive glands. Alimentary canal is complete and has well defined regions. It is concerned with ingestion, digestion, absorption and egestion of waste material.
Alimentary canal
It is a long coiled tube of about 8 to 10 meters long. It is of various diameter at various parts. It starts from mouth and ends in anus.
Different parts are:
Mouth
Vestibule
Buccal cavity
Pharynx
Oesophagus
Stomach
Small intestine
Large intestine
Anus
Mouth
It is a transverse slit like opening bounded by movable upper and lower lip. It opens into a small gap called vestibule. Vestibule is a space between lips and jaw. It opens not buccal cavity.
Buccal cavity
It is known as oral cavity or mouth cavity also. It is bounded by upper and lower jaws. The upper jaw is fixed and lower jaw is only movable up and down and sidewise. The jaws are provided with teeth in a row. At the floor, there is tongue. The roof of buccal cavity is made by palate.
Teeth
Human beings and most of other mammals are heterodont. They have different types of teeth with different functions.
1. incisors -- help to cut large piece into small pieces
2. canines -- help in tearing flesh
3. premolars – help in mastication
4. molars – help in mastication
They are diphyodont. They have two sets of teeth, milk teeth and permanent teeth.
Dental formula – it is expression of number and type of teeth on right or left side (one side) of jaw.
Dental formula of milk teeth i 2/2 c 1/1 pm 0/0 m2/2 5x2/5x2 = 20
Dental formula of permanent teeth i 2/2 c1/1 pm 2/2 m 3/3 8x2/8x2 = 32
i stands for incisor
c stands for canine
pm stands for premolar
m stands for molar
the numerator is for number of teeth in upper jaw
the denominator is for number of teeth in lower jaw
milk teeth start to drop out at about age of 5 or 6. the 3rd molar teeth are also known as wisdom teeth and appear at about the age of 17 to 21. teeth in females appear earlier than in males.
Structure of tooth
It has 3 regions
o Crown – part which project above gum
o Neck - part surrounded by gum
o Root - part embedded in bone, the incisor and canine and lower premolar have one root, upper premolar and lower molar have 2 roots and upper molar have 3 roots.
Tooth consists of enamel which is the hardest part of human body. It covers the dentine of crown. Dentine has many canaliculi that pass radially from the pulp cavity. Cement covers root of tooth. Periodontal membrane covers cement and fixes tooth in socket(thecodont).
Inside tooth, there is pulp cavity containing mass of cells, blood vessels and nerve constitute pulp. It is for growth of tooth. Dentine forming odontoblast and enamel forming ameloblast cells are also present.
Tongue
It is highly muscular organ attached at the floor of buccal cavity by a fold called frenulum. The upper surface is provided with numerous papillae containing taste buds. The taste buds are sensitive to taste of food.
Types of papillae
o Filliform- smallest, most numerous, conical, mostly found at center of tongue, white in color.
o Fungiform - less in no. red and rounded, found at tip and margin of tongue.
o Vallate papillae- large in size, about 5 to 12 in no. arranged in inverted v shape at the base of tongue.
o Foliate – leaf like, not developed in man, found at sides of tongue.
Tip of tongue – sweet
Sides of tongue – sour
Posterior end of tongue – bitter.
Functions of tongue
o Detects taste
o Helps in chewing, mix saliva
o Aids in swallowing
o Cleans teeth and gum
o Plays role in speech
Palate
The roof of buccal cavity is called palate. Anterior part is called hard palate. It bears transverse ridges called rugae. The posterior part is smooth and called as soft palate. The hinder part freely hangs down as a small flap called uvula.
Buccal cavity receives saliva from salivary gland.
Pharynx
It is wide opining at back of mouth cavity. It leads to two openings : gullet and glottis. There is a muscular flap called epiglottis which closes glottis when food is swallowed. There are 2 openings of internal nares above and two openings of Eustachian tubes at the sides.
It is the only part common to digestive and respiratory system.
Oesophagus
It is a long narrow muscular tube which connect mouth to stomach. It is about 25 cm long. It pierces diaphragm to open into stomach. It undergoes peristalsis to carry down food and water or fluid.
Stomach
It is a large muscular elastic bag situated below diaphragm on left side. It has four parts
o Cardiac – it is so called because it lies near heart. In between oesophagus and cardiac part of stomach there is cardiac sphincter.
o Fundus - it extends superiorly from the cardiac part. It is usually filled with air.
o Body - it is main part of stomach.
o Pyloric part - it is distal part of stomach. it opens into duodenum. It opens and closes several times. At the time of opening, a small amount of partially digested food(chime) is passed into duodenum.
Gastric gland secretes gastric juice.
Small intestine
It is divisible into 3 parts.
o Duodenum – it is c shaped and about 25 cm long. It receives bile juice and pancreatic juice through common bile duct.
o Jejunum - it is about 2.5 meter in length. It is coiled part.
o Ileum – it is about 3.5 meter long. It is highly coiled part. Both jejunum and ileum are suspended by mesenteries. The inner wall of ileum has number of folds called villi. It is mainly for digestion and absorption.
Large instestine
It is about 1.5 meter long and divisible into
o Caecum – it is pouch like structure about 6 cm long. There is ileocaecal valve preventing back flow. Attached to caecum is a slender vermiform appendix of about 10 cm long. It is vestigial in man but functional in herbivores. The inflammation of appendix is called appendicitis at the time of infection.
o Colon – it is inverted U shaped and divisible into
Ascending colon - it is the first part on right side. It moves upward from caecum.
Transverse colon - it is horizontal part.
Descending colon – it moves down at left side. It descends down
Pelvic colon – it is s shaped or sigmoid. Undigested material can remain in colon for about 36 hours.
Colon is for absorption of water mainly.
o Rectum - small muscular region, straight, about 15 cm long. It opens to the exterior through anus. Undigested material remains here for a short time. The anus is guarded by 2 sphincters
Through out the alimentary canal, mucous glands secrete mucus.
Digestive glands
Glands associated with alimentary canal.
Salivary glands
There are three pairs of salivary glands. There is one pair of Parotid gland. It is the largest of the salivary glands. It is situated near the ears. Stenson’s duct of Parotid gland open near the upper 2nd molar. One pair of sublingual glands are small and situated beneath tongue. Ducts of Rivinus open into floor of oral cavity. One pair of submandibular(also submaxillary) glands are medium sized and situated at angle of lower jaw. Warton’s duct open near the lower central incisors.
Salivary glands secrete saliva into oral cavity. Saliva is slightly acidic pH 6.8. About 1 to 1.5 Liter of saliva is secreted daily. Saliva contains starch digesting enzyme salivary amylase also called ptyalin.
Liver
It is the largest gland. It lies in the upper right side of abdominal cavity just below diaphragm. It is reddish brown and weighs about 1.4 to 1.5 Kg. It has two lobes right and left separated by falciform ligament. The right lobe is further divisible into right lobe proper, quadrate lobe and caudate lobe.
Gall bladder is a pear shaped sac like structure. It stores bile juice. The right and left hepatic ducts join to form common hepatic duct. It joins the cystic duct which arises from GB. The cystic duct and other hepatic duct join to form bile duct. It runs down to join the pancreatic duct to form hepatopancreatic duct. It opens into duodenum. The liver lobes are made up of small lobules called hepatic lobules. Hepatic lobules are separated by Glission’s capsule. Liver cells are arranged radially and separated by hepatic sinusoids(wide capillaries). Attached to liver cells there are kupffer’s cells which are phagocytic in nature.
Functions of liver
o Liver is main organ of Bile production. Bile contains bile pigment and salts. Bile pigments are Bilirubin(yellow) and biliverdin(green) used in coloration of bile and faeces. Salts of Sodium and Potassium bicarbonate neutralize acids. Sodium glycocholate and taurocholate help in emulsification.
o Deamination - NH2 amino group is removed from aminoacid resulting in the production of ammonia. Ammonia is converted into urea.
o Glycogenesis - it is conversion of excess glucose into glycogen with the help of insulin.
o Glycogenolysis - conversion of glycogen into glucose by liver cells with the help of glucagon.
o Lipogenesis - conversion of excess glucose and aminoacid into fats.
o Gluconeogenesis - formation of glucose or glycogen from non carbohydrate sources( aminoacid, fatty acid and glycerol). It also occurs in kidney and muscle.
o Detoxification – converts toxic substance into harmless substance eg harmful prussic acid is neutralized and rendered harmless.
o Haemopoises - formation of blood corpuscles, produces RBC in embryo.
o Destruction of RBC - old and worn out RBC broken down in liver.
o Synthesis of Blood protein - Prothrombin and fibrinogen are synthesized.
o Secretion of Heparin ( anticoagulant)
o Synthesis of vitamin A – synthesis of vitamin A from Beta carotene (carrot).
o Phagocytosis – Kupffer’s cell engulf microorganisms and dead cells.
o Production of heat - high metabolic activities, enough heat produced, maintain optimum body temperature, maintain homoestasis.
o Osmoregulation - produce angiotensinogen(protein) helping maintain body fluid.
o Storage – glycogen, fat, vitamins A D E K, comps of Fe Cu K etc.
o Lymph formation – important seat for lymph formation.
Pancreas
It is soft, lobulated, greenish pink gland. It weighs about 60 grams, 2.5 cm wide and 12 to 15 cm long. It located posterior to stomach. It comprises head, body and tail. Head lies in the curve of duodenum, body behind the stomach and tail reaches the spleen near left kidney.
The main pancreatic duct is formed by smaller ducts within pancreas. The main pancreatic duct open into hepatopancreatic ampulla.
Internal structure
It has two parts, Exocrine part and Endocrine part.
Exocrine part consists of rounded lobules(acini) which secrete alkaline pancreatic juice pH 8.4 about 500 to 800 ml of pancreatic juice secreted every day. The pancreatic juice contains 3 proenzyme, trypsinogen, chymotrypsinogen and procarboxypeptidase and some enzymes like pancreatic amylase, DNase, RNase, Lipase etc
Endocrine part consists of islet of Langerhans. About one million islets are found mostly in tail.
Types of cells
o Alpha cells - constitute about 25% , found at periphery, produce glucagon
o Beta cells - constitute 60% , found at middle, produce insulin
o Delta cells- constitute 10% found at periphery, produce somatostatin(SS).
Physiology of digestion
Man is omnivorous. It means man depends on plant materials and animal products. The food contains carbohydrate, protein and fats. The food is digested at different parts of alimentary canal.
Digestion in mouth
In mouth, the food is mixed with the saliva from salivary gland. Saliva contains the enzyme called salivary amylase. Salivary amylase acts on carbohydrate and changes some of carbohydrate into maltose, isomaltose and limit dextrine. Food remains in mouth for a short time so digestion is not complete.
Enzyme substrate products
Salivary amylase + starch ------------- maltose + isomaltase+ limit dextrine
Digestion in stomach
In the stomach, the gastric juice is secreted by gastric gland. Gastric juice contains pepsiongen, HCl and water. Peptic cells or zymogenic cells secrete pepsinogen. Parietal cells secrete HCl. Prorenin is found in infants.
Functions of HCl 1. converts inactive pepsinogen into active pepsin
2. provides acidic medium
3. stops growth of Bacteria
Pepsin changes inactive prorenin into active rennin. Pepsin acts on protein and changes it into peptones and proteoses. Rennin acts on milk casein. Milk casein is changed into paracasein. Paracasein combines with Calcium ion to form Calcium paracaseinate. It is then acted by pepsin and changed into peptones and proteoses. In the stomach, gastric lipase is also secreted. It acts on fats to change into fatty acids and glycerol.
Enzyme substrate products
Pepsin + protein --------- peptones + proteoses
Rennin + milk casein ------- paracasein
Paracasein + Ca ++ -- --- Calcium paracaseinate
Pepsin + Calcium paracaseinate --- peptones + proteoses
Lipase + fats -------------------- fatty acids and glycerol
Digestion in duodenum
The partially digested food called chime is passed on to the duodenum slowly. It is mixed with bile juice and pancreatic juice. The bile juice contains bile pigments and bile salts. The pancreatic juice contains enzymes like trypsinogen, amylase and lipase etc. The inactive trypsinogen is converted into active trypsin by enterokinase. Trypsin then acts on protein, peptones and proteoses and change into polypeptides. Amylase acts on starch and changes into maltose. Lipase acts on emulsified fat and change into fatty acids and glycerol.
The functions of bile 1. it neutralizes acids
2. it provides alkaline medium
3. it emulsifies fats
Enzyme substrate products
Trypsin + protein, proteoses, peptones ------ polypeptides
Amylase + starch ----------------------------- maltose
Lipase + emulsified fat ---------------------- fatty acids, glycerol
Digestion in jejunum and ileum
Here, intestinal juice is produced by crypts of Lieberkuhn. The intestinal juice contains aminopeptidase, dipeptidase, maltase, lactase, sucrase etc. the aminopeptidase acts on polypeptides and changes into smaller peptides. Dipeptidase acts on dipeptides and changes into aminoacids. Maltase acts on maltose. It is changed into glucose. Lactase acts on lactose to change that into galactose and glucose. Sucrase acts on sucrose and changed into fructose and glucose.
Enzyme substrate products
Aminopeptidase + polypeptides -------------------- smaller peptides
Dipeptidase + smaller peptides --------------- aminoacid
Maltase + maltose ------------------------- glucose
Lactose + lactose --------------------------- glucose and galactose
Sucrase + sucrose -------------------------- glucose and fructose
Absorption
Absorption takes place in the ileum mainly. For this, the internal lining of ileum is provided with large no. of finger like projections called villi. The villi increase the absorptive surface. These are provided with blood vessels and lymph. Glucose, aminoacid etc are absorbed into the blood vessel. Blood takes them to liver for storage of glucose. The fatty acids and glycerol come into the lymph which is taken into adipose tissue for storage.
Assimilation
Glucose, fatty acids and glycerol are used for the liberation of energy in the body. Aminoacids are used to produce protoplasm in the body for growth and repair of damaged tissue.
Egestion
Undigested materials are passed into large intestine. Water is absorbed here. Then these are carried down. Lastly undigested materials are discharged out from anus. It is called egestion.
Human beings are heterotrophic. It means they can not manufacture their food and depend upon plants or other animals. They have holozoic type of nutrition. The nutrition is animal like. Human beings are omnivorous in nature.
The digestive system consists of alimentary canal and digestive glands. Alimentary canal is complete and has well defined regions. It is concerned with ingestion, digestion, absorption and egestion of waste material.
Alimentary canal
It is a long coiled tube of about 8 to 10 meters long. It is of various diameter at various parts. It starts from mouth and ends in anus.
Different parts are:
Mouth
Vestibule
Buccal cavity
Pharynx
Oesophagus
Stomach
Small intestine
Large intestine
Anus
Mouth
It is a transverse slit like opening bounded by movable upper and lower lip. It opens into a small gap called vestibule. Vestibule is a space between lips and jaw. It opens not buccal cavity.
Buccal cavity
It is known as oral cavity or mouth cavity also. It is bounded by upper and lower jaws. The upper jaw is fixed and lower jaw is only movable up and down and sidewise. The jaws are provided with teeth in a row. At the floor, there is tongue. The roof of buccal cavity is made by palate.
Teeth
Human beings and most of other mammals are heterodont. They have different types of teeth with different functions.
1. incisors -- help to cut large piece into small pieces
2. canines -- help in tearing flesh
3. premolars – help in mastication
4. molars – help in mastication
They are diphyodont. They have two sets of teeth, milk teeth and permanent teeth.
Dental formula – it is expression of number and type of teeth on right or left side (one side) of jaw.
Dental formula of milk teeth i 2/2 c 1/1 pm 0/0 m2/2 5x2/5x2 = 20
Dental formula of permanent teeth i 2/2 c1/1 pm 2/2 m 3/3 8x2/8x2 = 32
i stands for incisor
c stands for canine
pm stands for premolar
m stands for molar
the numerator is for number of teeth in upper jaw
the denominator is for number of teeth in lower jaw
milk teeth start to drop out at about age of 5 or 6. the 3rd molar teeth are also known as wisdom teeth and appear at about the age of 17 to 21. teeth in females appear earlier than in males.
Structure of tooth
It has 3 regions
o Crown – part which project above gum
o Neck - part surrounded by gum
o Root - part embedded in bone, the incisor and canine and lower premolar have one root, upper premolar and lower molar have 2 roots and upper molar have 3 roots.
Tooth consists of enamel which is the hardest part of human body. It covers the dentine of crown. Dentine has many canaliculi that pass radially from the pulp cavity. Cement covers root of tooth. Periodontal membrane covers cement and fixes tooth in socket(thecodont).
Inside tooth, there is pulp cavity containing mass of cells, blood vessels and nerve constitute pulp. It is for growth of tooth. Dentine forming odontoblast and enamel forming ameloblast cells are also present.
Tongue
It is highly muscular organ attached at the floor of buccal cavity by a fold called frenulum. The upper surface is provided with numerous papillae containing taste buds. The taste buds are sensitive to taste of food.
Types of papillae
o Filliform- smallest, most numerous, conical, mostly found at center of tongue, white in color.
o Fungiform - less in no. red and rounded, found at tip and margin of tongue.
o Vallate papillae- large in size, about 5 to 12 in no. arranged in inverted v shape at the base of tongue.
o Foliate – leaf like, not developed in man, found at sides of tongue.
Tip of tongue – sweet
Sides of tongue – sour
Posterior end of tongue – bitter.
Functions of tongue
o Detects taste
o Helps in chewing, mix saliva
o Aids in swallowing
o Cleans teeth and gum
o Plays role in speech
Palate
The roof of buccal cavity is called palate. Anterior part is called hard palate. It bears transverse ridges called rugae. The posterior part is smooth and called as soft palate. The hinder part freely hangs down as a small flap called uvula.
Buccal cavity receives saliva from salivary gland.
Pharynx
It is wide opining at back of mouth cavity. It leads to two openings : gullet and glottis. There is a muscular flap called epiglottis which closes glottis when food is swallowed. There are 2 openings of internal nares above and two openings of Eustachian tubes at the sides.
It is the only part common to digestive and respiratory system.
Oesophagus
It is a long narrow muscular tube which connect mouth to stomach. It is about 25 cm long. It pierces diaphragm to open into stomach. It undergoes peristalsis to carry down food and water or fluid.
Stomach
It is a large muscular elastic bag situated below diaphragm on left side. It has four parts
o Cardiac – it is so called because it lies near heart. In between oesophagus and cardiac part of stomach there is cardiac sphincter.
o Fundus - it extends superiorly from the cardiac part. It is usually filled with air.
o Body - it is main part of stomach.
o Pyloric part - it is distal part of stomach. it opens into duodenum. It opens and closes several times. At the time of opening, a small amount of partially digested food(chime) is passed into duodenum.
Gastric gland secretes gastric juice.
Small intestine
It is divisible into 3 parts.
o Duodenum – it is c shaped and about 25 cm long. It receives bile juice and pancreatic juice through common bile duct.
o Jejunum - it is about 2.5 meter in length. It is coiled part.
o Ileum – it is about 3.5 meter long. It is highly coiled part. Both jejunum and ileum are suspended by mesenteries. The inner wall of ileum has number of folds called villi. It is mainly for digestion and absorption.
Large instestine
It is about 1.5 meter long and divisible into
o Caecum – it is pouch like structure about 6 cm long. There is ileocaecal valve preventing back flow. Attached to caecum is a slender vermiform appendix of about 10 cm long. It is vestigial in man but functional in herbivores. The inflammation of appendix is called appendicitis at the time of infection.
o Colon – it is inverted U shaped and divisible into
Ascending colon - it is the first part on right side. It moves upward from caecum.
Transverse colon - it is horizontal part.
Descending colon – it moves down at left side. It descends down
Pelvic colon – it is s shaped or sigmoid. Undigested material can remain in colon for about 36 hours.
Colon is for absorption of water mainly.
o Rectum - small muscular region, straight, about 15 cm long. It opens to the exterior through anus. Undigested material remains here for a short time. The anus is guarded by 2 sphincters
Through out the alimentary canal, mucous glands secrete mucus.
Digestive glands
Glands associated with alimentary canal.
Salivary glands
There are three pairs of salivary glands. There is one pair of Parotid gland. It is the largest of the salivary glands. It is situated near the ears. Stenson’s duct of Parotid gland open near the upper 2nd molar. One pair of sublingual glands are small and situated beneath tongue. Ducts of Rivinus open into floor of oral cavity. One pair of submandibular(also submaxillary) glands are medium sized and situated at angle of lower jaw. Warton’s duct open near the lower central incisors.
Salivary glands secrete saliva into oral cavity. Saliva is slightly acidic pH 6.8. About 1 to 1.5 Liter of saliva is secreted daily. Saliva contains starch digesting enzyme salivary amylase also called ptyalin.
Liver
It is the largest gland. It lies in the upper right side of abdominal cavity just below diaphragm. It is reddish brown and weighs about 1.4 to 1.5 Kg. It has two lobes right and left separated by falciform ligament. The right lobe is further divisible into right lobe proper, quadrate lobe and caudate lobe.
Gall bladder is a pear shaped sac like structure. It stores bile juice. The right and left hepatic ducts join to form common hepatic duct. It joins the cystic duct which arises from GB. The cystic duct and other hepatic duct join to form bile duct. It runs down to join the pancreatic duct to form hepatopancreatic duct. It opens into duodenum. The liver lobes are made up of small lobules called hepatic lobules. Hepatic lobules are separated by Glission’s capsule. Liver cells are arranged radially and separated by hepatic sinusoids(wide capillaries). Attached to liver cells there are kupffer’s cells which are phagocytic in nature.
Functions of liver
o Liver is main organ of Bile production. Bile contains bile pigment and salts. Bile pigments are Bilirubin(yellow) and biliverdin(green) used in coloration of bile and faeces. Salts of Sodium and Potassium bicarbonate neutralize acids. Sodium glycocholate and taurocholate help in emulsification.
o Deamination - NH2 amino group is removed from aminoacid resulting in the production of ammonia. Ammonia is converted into urea.
o Glycogenesis - it is conversion of excess glucose into glycogen with the help of insulin.
o Glycogenolysis - conversion of glycogen into glucose by liver cells with the help of glucagon.
o Lipogenesis - conversion of excess glucose and aminoacid into fats.
o Gluconeogenesis - formation of glucose or glycogen from non carbohydrate sources( aminoacid, fatty acid and glycerol). It also occurs in kidney and muscle.
o Detoxification – converts toxic substance into harmless substance eg harmful prussic acid is neutralized and rendered harmless.
o Haemopoises - formation of blood corpuscles, produces RBC in embryo.
o Destruction of RBC - old and worn out RBC broken down in liver.
o Synthesis of Blood protein - Prothrombin and fibrinogen are synthesized.
o Secretion of Heparin ( anticoagulant)
o Synthesis of vitamin A – synthesis of vitamin A from Beta carotene (carrot).
o Phagocytosis – Kupffer’s cell engulf microorganisms and dead cells.
o Production of heat - high metabolic activities, enough heat produced, maintain optimum body temperature, maintain homoestasis.
o Osmoregulation - produce angiotensinogen(protein) helping maintain body fluid.
o Storage – glycogen, fat, vitamins A D E K, comps of Fe Cu K etc.
o Lymph formation – important seat for lymph formation.
Pancreas
It is soft, lobulated, greenish pink gland. It weighs about 60 grams, 2.5 cm wide and 12 to 15 cm long. It located posterior to stomach. It comprises head, body and tail. Head lies in the curve of duodenum, body behind the stomach and tail reaches the spleen near left kidney.
The main pancreatic duct is formed by smaller ducts within pancreas. The main pancreatic duct open into hepatopancreatic ampulla.
Internal structure
It has two parts, Exocrine part and Endocrine part.
Exocrine part consists of rounded lobules(acini) which secrete alkaline pancreatic juice pH 8.4 about 500 to 800 ml of pancreatic juice secreted every day. The pancreatic juice contains 3 proenzyme, trypsinogen, chymotrypsinogen and procarboxypeptidase and some enzymes like pancreatic amylase, DNase, RNase, Lipase etc
Endocrine part consists of islet of Langerhans. About one million islets are found mostly in tail.
Types of cells
o Alpha cells - constitute about 25% , found at periphery, produce glucagon
o Beta cells - constitute 60% , found at middle, produce insulin
o Delta cells- constitute 10% found at periphery, produce somatostatin(SS).
Physiology of digestion
Man is omnivorous. It means man depends on plant materials and animal products. The food contains carbohydrate, protein and fats. The food is digested at different parts of alimentary canal.
Digestion in mouth
In mouth, the food is mixed with the saliva from salivary gland. Saliva contains the enzyme called salivary amylase. Salivary amylase acts on carbohydrate and changes some of carbohydrate into maltose, isomaltose and limit dextrine. Food remains in mouth for a short time so digestion is not complete.
Enzyme substrate products
Salivary amylase + starch ------------- maltose + isomaltase+ limit dextrine
Digestion in stomach
In the stomach, the gastric juice is secreted by gastric gland. Gastric juice contains pepsiongen, HCl and water. Peptic cells or zymogenic cells secrete pepsinogen. Parietal cells secrete HCl. Prorenin is found in infants.
Functions of HCl 1. converts inactive pepsinogen into active pepsin
2. provides acidic medium
3. stops growth of Bacteria
Pepsin changes inactive prorenin into active rennin. Pepsin acts on protein and changes it into peptones and proteoses. Rennin acts on milk casein. Milk casein is changed into paracasein. Paracasein combines with Calcium ion to form Calcium paracaseinate. It is then acted by pepsin and changed into peptones and proteoses. In the stomach, gastric lipase is also secreted. It acts on fats to change into fatty acids and glycerol.
Enzyme substrate products
Pepsin + protein --------- peptones + proteoses
Rennin + milk casein ------- paracasein
Paracasein + Ca ++ -- --- Calcium paracaseinate
Pepsin + Calcium paracaseinate --- peptones + proteoses
Lipase + fats -------------------- fatty acids and glycerol
Digestion in duodenum
The partially digested food called chime is passed on to the duodenum slowly. It is mixed with bile juice and pancreatic juice. The bile juice contains bile pigments and bile salts. The pancreatic juice contains enzymes like trypsinogen, amylase and lipase etc. The inactive trypsinogen is converted into active trypsin by enterokinase. Trypsin then acts on protein, peptones and proteoses and change into polypeptides. Amylase acts on starch and changes into maltose. Lipase acts on emulsified fat and change into fatty acids and glycerol.
The functions of bile 1. it neutralizes acids
2. it provides alkaline medium
3. it emulsifies fats
Enzyme substrate products
Trypsin + protein, proteoses, peptones ------ polypeptides
Amylase + starch ----------------------------- maltose
Lipase + emulsified fat ---------------------- fatty acids, glycerol
Digestion in jejunum and ileum
Here, intestinal juice is produced by crypts of Lieberkuhn. The intestinal juice contains aminopeptidase, dipeptidase, maltase, lactase, sucrase etc. the aminopeptidase acts on polypeptides and changes into smaller peptides. Dipeptidase acts on dipeptides and changes into aminoacids. Maltase acts on maltose. It is changed into glucose. Lactase acts on lactose to change that into galactose and glucose. Sucrase acts on sucrose and changed into fructose and glucose.
Enzyme substrate products
Aminopeptidase + polypeptides -------------------- smaller peptides
Dipeptidase + smaller peptides --------------- aminoacid
Maltase + maltose ------------------------- glucose
Lactose + lactose --------------------------- glucose and galactose
Sucrase + sucrose -------------------------- glucose and fructose
Absorption
Absorption takes place in the ileum mainly. For this, the internal lining of ileum is provided with large no. of finger like projections called villi. The villi increase the absorptive surface. These are provided with blood vessels and lymph. Glucose, aminoacid etc are absorbed into the blood vessel. Blood takes them to liver for storage of glucose. The fatty acids and glycerol come into the lymph which is taken into adipose tissue for storage.
Assimilation
Glucose, fatty acids and glycerol are used for the liberation of energy in the body. Aminoacids are used to produce protoplasm in the body for growth and repair of damaged tissue.
Egestion
Undigested materials are passed into large intestine. Water is absorbed here. Then these are carried down. Lastly undigested materials are discharged out from anus. It is called egestion.
Monday, February 8, 2010
for Grade XI and XII
Unit wise weightage for Zoology grade XI
1. Introduction to Biology - very short questions 2, short questions x, long questions x.
2. evolution of life – very short questions 2 or 1 opt, short questions 0 or 1 opt, long question 1( 8 marks)
3. biodiversity – very short questions 1 or 1 opt, short questions 3 or 1 opt, long questions 1 or 1 opt (7.5 marks)
4. biota and their environment – very short questions 2 or 1 opt, short questions 2, long questions x
one full question of 8 marks will be asked either from the unit Evolution of life or Biota and environment.
Unit wise weightage for Zoology grade XII
1. Anatomy and physiology of organisms – very short question 1, short questions 1, long questions x.
2. Developmental biology – very short questions x or 1 opt, short questions 1, long questions x
3. Human biology and health- very short questions 3 or 2 opt, short questions 2 or 1 opt , long questions 1(8 marks) and 1( 7.5 marks) or 1 opt
4. Application of biology – short questions 3, short questions 1, long questions x
Long question from Developmental biology can be asked by reducing the marks from the unit of Human Biology and Health.
1. Introduction to Biology - very short questions 2, short questions x, long questions x.
2. evolution of life – very short questions 2 or 1 opt, short questions 0 or 1 opt, long question 1( 8 marks)
3. biodiversity – very short questions 1 or 1 opt, short questions 3 or 1 opt, long questions 1 or 1 opt (7.5 marks)
4. biota and their environment – very short questions 2 or 1 opt, short questions 2, long questions x
one full question of 8 marks will be asked either from the unit Evolution of life or Biota and environment.
Unit wise weightage for Zoology grade XII
1. Anatomy and physiology of organisms – very short question 1, short questions 1, long questions x.
2. Developmental biology – very short questions x or 1 opt, short questions 1, long questions x
3. Human biology and health- very short questions 3 or 2 opt, short questions 2 or 1 opt , long questions 1(8 marks) and 1( 7.5 marks) or 1 opt
4. Application of biology – short questions 3, short questions 1, long questions x
Long question from Developmental biology can be asked by reducing the marks from the unit of Human Biology and Health.
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