NUTRITION IN ANIMALS
Holozoic Nutrition: The heterotrophic nutrition in which the organisms consume solid organic matter as their food is called holozoic nutrition. It
means ingestion of complex organic substances without being degraded or decomposed. After intake of such food, enzymes
produced within the organisms digest it . Digested food stuffs are absorbed into the body and the undigested product is
removed from the body (egestion). This kind of nutrition is found in Amoeba.
Ingestion: The process by which food is taken by the organisms is called ingestion. Or the process of taking of food into the body by the
organism is called Ingestion.
Digestion: The process of breaking down of complex food molecules into simpler absorbable molecules with the help of enzymes is called
digestion.
Absorption: The process by which the digested food molecules are taken up or absorbed into the blood vessels in the wall of the intestine
and sent to the circulatory system is called absorption.
Assimilation: The incorporation or transportation of absorbed food into living cells and its utilization by the body for its growth is called
assimilation.
Egestion: The process by which undigested food is removed from the body is called egestion.
Pseudopodium: In simple organism like Amoeba, food is taken in from any place by means of false foot called pseudopodium.( plural of
pseudopodium is pseudopodia)
Alimentary canal: The canal through which food passes is called food canal or alimentary canal. It is a long, muscular and coiled tube. The different
compartments of alimentary canal are buccal cavity, oesophagus, stomach, small intestine, large intestine, rectum and anus. It
is also called digestive tract.
Digestive system: The digestive tract and the associated glands together constitute digestive system.
Milk teeth: The first set of teeth grows during infancy which fall off at the age between 6 to 8 years is called milk teeth. These are 20 in
numbers. The first tooth appears in the centre of the lower jaw.
Permanent teeth: The second set of teeth that replaces the milk teeth is the permanent teeth.
Incisors; The front four teeth in each jaw are called incisors. Total number of incisors in the mouth are 8.(4 in lower jaw and 4 in upper
jaw). Incisors are flat and help in biting the food.
Canines: On either side of the incisors are the canines. Canines are two in number in each jaw. Total number of canines in the mouth is 4.
(2 in lower jaw and 2 in upper jaw). They are sharp and meant for tearing the food.
Premolars: Premolars are behind the canines, and two in number on either side in each jaw. Total number of premolars in the mouth is 8.
( 4 in lower jaw and 4 in the upper jaw ). These teeth are used for grinding and crushing the food.
Molars: Molars are behind the premolars. In an adult, they are 6 in numbers in each jaw, three each on either side. Total number of
molars in the mouth is 12. (6 in lower jaw and 6 in upper jaw). These teeth are used for grinding and crushing the food.
Wisdom teeth: In young people, there are 8 molars in all. The second set of 4 molars appears at the age of 18 or even later. These are called
wisdom teeth.
Tooth decay: The bacteria present in the mouth break down the sugars present from the left over food and release acids which gradually
damage the teeth. This is called tooth decay.
Dental plaque: Saliva and bacteria present in the mouth stick to the teeth and form a sticky film which is called dental plaque.
Mastication: The process of chewing the food is called mastication.
Taste bud: The tongue has sense organs called the taste bud. These buds distinguish four basic tastes, salty, sour, sweet and bitter.
Salivary glands: There are 3 pairs of salivary glands in our mouth. A watery material called saliva is secreted by these glands. Saliva contains an
enzyme called amylase also called ptyalin, which changes starch into sugar called maltose.
Oesophagus: It is also called gullet. Food pipe
Liver : The reddish brown gland situated in the upper part of the abdomen on the right side which secretes bile is called liver. It is the
largest gland in the body. The bile secreted by the liver is stored in a sac called the gall bladder. Bile plays an important role in the
digestion of fats.
Gall bladder: The bile juice secreted by the liver is stored in a sac called the gall bladder.
Pancreas : Pancreas is a large cream coloured gland located just below the stomach. It secretes insulin. The pancreatic juice acts on
carbohydrates, fats and proteins and changes them into simpler forms.
Villi: ‘Villi’ is the plural of ‘villus’. The inner surface of the small intestine has a number of finger-like projections called villi. The function
of the villi is to increase the surface area for absorption of digested food.. Each villus has a network of thin and small blood
vessels close to its surface. The surface of the villi absorbs the digested food materials
Chewing cud: Grass-eating animals swallow the grass and latter they bring back the partially digested grass called cud from the rumen and
chew thoroughly. This is called chewing of the cud.
Rumination: The process of bringing back the partially digested cud from the rumen to the mouth and chewing it is called rumination. Or the
process of chewing cud is called rumination.
Rumen: In grass-eating animals, the swallowed grass is stored in a part of the stomach called rumen.
Cud: The partially digested grass in the rumen is called cud.
Ruminants: All animals who chew cud are called ruminants.
Extracellular digestation: Digestion outside cells in higher complex organisms because of presence of special organs (alimentary canals) is called
extracellular digestion.
Intracellular digestion: Digestion within cells in lower animals is called intracellular digestion. The food particles directly enter the cells and get digested.
Food vacuole: In amoeba the food is digested in the food vacuole.
Compound stomach: In ruminants the stomach has four chambers. They are rumen, reticulum, omasum and obomasum. Such a stomach is
called compound stomach.
Cellulose: Cellulose is a complex carbohydrate. It is also a tasteless white powdery material. It can be digested by ruminants only because
of the presence of certain bacteria and enzyme in their body. But that can not be digested by the humans because of the
absence of these bacteria and enzyme in human body to break it down. As a result, it is excreted out as such. Therefore, it does
not provide any energy to our body.
FILL IN THE BLANKS
PRIVATE BOOK QUESTIONS
STUDY QUESTIONS
I. Multiple Choice questions: Tick the correct answer.
1. Which of the following helps in the digestion of food ?
a) Nutrients b) Hormones c) Enzymes or juices d) Saliva
2. Saliva contains an enzyme called
a) Amylase b) Trypsin c) Pepsin d) None of these
3. The teeth adapted for flesh eating are
a) Incisors b) Premolars c) Canines d) Molars
4. Finger-like projections called villi are present in
a) Stomach b) Large intestine c) small intestine d) Liver
5. Most of digestion of food takes place in
a) Stomach b) Small intestine c) Large intestine d) Rectum
6. Absorption of food takes place in
a) Small intestine b) Pancreas c) Large intestine d) Liver
7. Absorption of water takes place in
a) Small intestine b) Large intestine c) Rectum d) Large intestine &rectum
II. Fill in the blanks
1. Saliva is secreted by the Salivary glands in the mouth cavity.
2. Number of molar teeth present in an human adult are 12.
3. The teeth which help in biting the food in humans are the incisors.
4. .Food is digested by chemicals called
5. Changing food to a usable simpler form is called digestion.
6. The liver and pancreas are found near the stomach..
7. The five steps in the process of nutrition are ingestion, digestion, absorption,
assimilation, egestion.
8. The largest gland in the human body is liver.
9. Amoeba digests its food in the food vacuole.
10. Taking in food from outside is called ingestion.
11. The longest part of the digestive tract in humans is the small intestine
12. Finger-like projections called villi are present in small intestine.
13. In amoeba pseudopodium are used for procuring food.
14. Absorption of food takes place through villi in the small intestine.
15. Number of molar teeth present in an human adult is 12. ( 6 in each jaw)
III. True or False
1. Canines are meant for tearing flesh. TRUE
2. Molar teeth are present in a human baby. FALSE
3. Mouth cavity is also known as food pipe. FALSE
4. Gastric juice is secreted by the small intestine. FALSE
5. Food is mostly digested by stomach. FALSE
6. In humans, there are 14 teeth in each jaw. FALSE
7. HCL is secreted in the stomach. TRUE
8. Deer is ruminant. TRUE.
9. Chewing of cud is shown by ruminants. TRUE
10. Food pipe is present in the neck TRUE
11. Tongue helps in mixing food with saliva. TRUE
IV. Match the column
Column A Column B
1. Amoeba Food vacuole
2. Cow Ruminant
3. Stomach HCL acid secreted
4. Liver Bile juice secretion
5. Small intestine Digestion completed
6. Large intestine Absorb water
7. Rectum storage of undigested food material
8. Salivary gland saliva
V. Define the following terms:
Answers are on first page
VI. Name the different organs of the digestive system.
1. Mouth and mouth cavity or buccal cavity
2. Oesophagus ( gullet or food pipe)
3. Stomach
4. Small intestine
5. Large intestine
6. Rectum
7. Anus
8. Salivary glands
9. Liver
10. Pancreas.
2. Canines 2 + 2 = 4 for tearing the food
3. Premolars 4 + 4 = 8 for grinding and crushing the food
4. Molars 6 + 6 =12 for grinding and crushing the food
No.1. How is digestive system different from an alimentary canal?
Ans. Alimentary canal or digestive tract is a long, muscular and coiled tube which starts from the mouth and ends at anus. The different organs of the alimentary canal are :
1. Mouth and mouth cavity or buccal cavity
2. Oesophagus ( gullet or food pipe)
3. Stomach
4. Small intestine
5. Large intestine
6. Rectum
7. Anus
The alimentary canals and the associated glands such as salivary glands, liver and pancreas together constitute the digestive system.
No.2. Give the functions of different types of teeth in an adult human.
There are four different types of teeth in an adult human. They are
1. Incisors 4 + 4 = 8 for biting the food
2. Canines 2 + 2 = 4 for tearing the food
3. Premolars 4 + 4 = 8 for grinding and crushing the food
4. Molars 6 + 6 =12 for grinding and crushing the food
No.3. Describe the functions of the followings.
a) Saliva: Saliva is a watery material secreted by three pairs of salivary glands in our mouth. The function of saliva is to help in the digestion of food. It contains an enzyme called amylase (also called ptyalin) which acts on starch and changes the starch into a sugar called maltose.
b) Oesophagus: It is also called gullet or food pipe. It connects the mouth cavity with the stomach. It runs along the neck and the chest. No digestion takes place here. The function of the oesophagus is to help in pushing the food into stomach. Vomiting takes place when the food is not accepted by the stomach.
c) Tongue: Tongue is a muscular organ. The functions of the tongue are :
1) It helps in mixing the masticated food with saliva
2) It helps in swallowing down the food.
3) It tastes, as it bears taste buds.
4) It helps in speaking.
d) Liver: It is the largest gland of the body. The function of the liver is to secrete bile juice which helps in digestion of facts and is stored in a small bag called the gall bladder.
No.4. Explain the digestive systems in humans with the help of a diagram.
Ans. The Alimentary canal and the other associative glands together make the digestive system. The different parts of the alimentary canal are mouth ( buccal cavity), food pipe ( oesophagus ), stomach, small intestine, large intestine rectum and anus.
a) Mouth: The digestion starts in the mouth itself. The food is masticated with the help of different types of teeth. The masticated food gets mixed with saliva secreted by the salivary glands with the help of the tongue. Amylase or ptyalin, an enzyme present in the saliva acts on starch present in the food and converts it into a sugar called maltose. Then the food is swallowed down.
b) Food pipe: The food pipe or gullet is also called oesophagus. . It connects the mouth cavity with the stomach. The swallowed food passes to the stomach through oesophagus. Food is pushed down by the movement of the walls of the food pipe called peristalsis. movement.
c) Stomach: The stomach is a muscular bag lying in the upper abdomen. Here the food is churned and converted into a semi solid paste and mixes with gastric juice secreted in the stomach. The pepsin present in the gastric juice acts on the proteins and convert them into peptides and amino acids. This partially digested food then passes to the small intestine.
d) Small intestine: The small intestine is a long coiled tube. The intestinal juice digests all type of food and converts them to glucose, amino acids and fatty acids. These simpler substances are absorbed by villi present in the inner wall of the small intestine and passes to the circulatory system through the blood vessels. Digestion is completed here.
e) Large intestine; Large intestine has no digestive function to carry out. It helps in absorbing water and salt from the undigested food.
No.5. Is the large intestine really large?
Ans. No, the large intestine is not really large. It is smaller than the small intestine. The large intestine is about 1.5. meters long , while the small intestine is 6 metres long.
No.6. Where does digestion start in humans?
Ans. Digestion in human starts in mouth. The ingested food is masticated by the teeth and gets mixed with the saliva secreted by the salivary glands. From here the digestion starts.
No.7. Mention various steps in the process of digestion.
Ans. As q.no.4 above
No.8. Where is bile produced? Which component of food does it digest?
Ans. Bile is produced in liver, which is the largest gland of the body. The secreted bile is stored in a small bag called gall bladder. It digests fats.
No.9. Where are villi found and what is their function?
Ans. Villi are finger like projections or outgrowths found in the inner surface of the small intestine. The function of villi is to increase the surface area for absorption of digested food. Each villus has a network of thin and small blood vessels close to its surface. The surface of the villi absorbs the digested food materials which are transported via blood vessels to different organs of the body.
No.10. How does digestion take place in ruminant?
Ans. Ruminant has compound stomach. It has four chambers; rumen, reticulum, omasum and obomasum. The ingested food enters the first chamber called rumen. From rumen, the food enters the second chamber (reticulum). In these two chambers, the food is partially digested and converted into a soft pulp called the cud. In relax time the cud from the second chamber is brought back to the mouth and chewed thoroughly. This process of chewing cud is called rumination. During rumination, cud mixes with saliva and becomes a semi-liquid paste. From the mouth the semi-liquid paste food is pushed into the third chamber (omasum). From the third chamber (omasum), the food enters the fourth chamber (obomasum). In the fourth chamber, digestive juices are mixed with the semi-liquid food and digestion of food then starts. From the fourth chamber, the food enters the small intestine.
No.11. How is the nutrition in Amoeba different from that in human beings?
Ans. Amoeba is a microscopic, single-celled organism without having a mouth or a digestive system. It comes near its food and take in the food by means of false feet or pseudopodia. The food particle with a drop of water forms a food vacuole. The ingested food in the food vacuole is digested with the help of digestive juices (enzymes) produced within the body. The digestion in amoeba is intracellular. The digested food is then absorbed into the cell cytoplasm and the undigested food material is removed from the body at any point through a temporary vacuole.
Whereas, in case of human beings, the five steps of nutrition are ingestion, digestion, absorption, assimilation and egestion. Humans have special organs in their bodies for each of these steps. In case of humans, ingestion occurs in the mouth and the hands are used for this purpose.. The digestion in human beings is extracellular. The process of digestion starts in mouth. The masticated food gets mixed with saliva secreted by the salivary glands. Amylase or ptyalin , an enzyme present in the saliva acts on starch present in the food and convert it into a sugar called maltose. Then the food passes to the stomach through the oesophagus. In the stomach the food is churned and converted into a semi-solid paste and mixes with gastric juice secreted in the stomach. The pepsin present in the gastric juice acts on the proteins and convert them into peptides and amino acids. This partially digested food then passes to the small intestine. The intestinal juice digests all types of food and converts them to glucose, amino acids and fatty acids. These simpler substances are absorbed by villi present in the inner wall of small intestine and passes to circulatory system through blood vessels. The undigested food materials pass to the large intestine where water is absorbed. Then the undigested waste materials pass to the rectum and excreted out through anus as faeces.
NCERT BOOK
1. Fill in the blanks
a) The main steps of nutrition in humans are ingestion, digestion, absorption,
assimilation, egestion.
b) The largest gland in the human body is liver.
c) The stomach releases hydrochloric acid and digestive juices which act on food.
d) The inner wall of small intestine has many fingerlike out growth called villi.
e) Amoeba digests it food in the food vacuole.
2. True or False
a) Digestion of starch starts in mouth. TRUE
b) The tongue helps in mixing food with saliva. TRUE
c) The gall bladder temporarily stores bile. TRUE
d) The ruminants bring back the swallowed grass into their mouth and chew it for sometimes TRUE
3. Tick the correct answer.
a) Fat is completely digested in the
i) Stomach ii) mouth iii) small intestine iv) large intestine
b) Water from the undigested food is absorbed mainly in the
i) Stomach ii) food pipe iii) small intestine iv) large intestine
4. Match the column
Column A Column B
Food components products of digestion
Carbohydrates sugars
Proteins amino acids
Fats fatty acids and glycerol
5. What are villi? What is their location and function?
Ans. ‘Villi’ is the plural of ‘villus’. The inner surface of the small intestine has a number of finger-like projections or outgrowths called villi, The function of the villi is to increase the surface area for absorption of digested food.. Each villus has a network of thin and small blood vessels close to its surface. The surface of the villi absorbs the digested food materials.
6. Where is the bile produced? Which component of the food does it help to digest ?
Ans. The bile is produced in the liver, which is the largest gland of the body. It is reddish brown in colour and situated in the upper part of the abdomen on the right side. The bile secreted by the liver is stored in the gall bladder and received in the small intestine which helps in the digestion of fats.
7. Name the types of carbohydrates that can be digested by ruminants but not by humans. Give the reasons also.
Ans. Cellulose is a complex carbohydrate. It is also a tasteless white powdery material. It can be digested by ruminants only because of the presence of certain bacteria and enzyme in their body. But that can not be digested by the humans because of the absence of these bacteria and enzyme in human body to break it down. As a result, it is excreted out as such. Therefore, it does not provide any energy to our body.
8.. Why do we get instant energy from glucose?
Ans. Carbohydrates are the main source of energy. It is converted into glucose ( C6 H12 O6 ). Glucose is a typical carbohydrate which directly enters the blood stream and produces energy through respiration immediately. Therefore, we get instant energy from glucose.
9. Which part of the digestive canal is involved in :
i) Absorption of food : Small intestine
ii) Chewing of food : Buccal cavity
iii) Killing of bacterial : Stomach
iv) Complete digestion of food : Small intestine
v) Formation of faeces
10. Write one similarity and one difference between the nutrition in amoeba and human.
Ans. One similarity in nutrition between amoeba and humans is that there are five process of digestion in both organisms. (Ingestion, digestion, absorption, assimilation and egestion).
One difference in between amoeba and humans is that in humans digestion of food takes place in many parts but in amoeba digestion of food takes place in single cell.
11. Match the items of Column I with suitable items in Column II
Column I Column II
a) Salivary gland Saliva secretion
b) Stomach Acid release
c) Liver Bile juice secretion
d) Rectum storage of undigested food
e) Small intestine Digestion is completed
f) Large intestine Absorption of water
Holozoic Nutrition: The heterotrophic nutrition in which the organisms consume solid organic matter as their food is called holozoic nutrition. It
means ingestion of complex organic substances without being degraded or decomposed. After intake of such food, enzymes
produced within the organisms digest it . Digested food stuffs are absorbed into the body and the undigested product is
removed from the body (egestion). This kind of nutrition is found in Amoeba.
Ingestion: The process by which food is taken by the organisms is called ingestion. Or the process of taking of food into the body by the
organism is called Ingestion.
Digestion: The process of breaking down of complex food molecules into simpler absorbable molecules with the help of enzymes is called
digestion.
Absorption: The process by which the digested food molecules are taken up or absorbed into the blood vessels in the wall of the intestine
and sent to the circulatory system is called absorption.
Assimilation: The incorporation or transportation of absorbed food into living cells and its utilization by the body for its growth is called
assimilation.
Egestion: The process by which undigested food is removed from the body is called egestion.
Pseudopodium: In simple organism like Amoeba, food is taken in from any place by means of false foot called pseudopodium.( plural of
pseudopodium is pseudopodia)
Alimentary canal: The canal through which food passes is called food canal or alimentary canal. It is a long, muscular and coiled tube. The different
compartments of alimentary canal are buccal cavity, oesophagus, stomach, small intestine, large intestine, rectum and anus. It
is also called digestive tract.
Digestive system: The digestive tract and the associated glands together constitute digestive system.
Milk teeth: The first set of teeth grows during infancy which fall off at the age between 6 to 8 years is called milk teeth. These are 20 in
numbers. The first tooth appears in the centre of the lower jaw.
Permanent teeth: The second set of teeth that replaces the milk teeth is the permanent teeth.
Incisors; The front four teeth in each jaw are called incisors. Total number of incisors in the mouth are 8.(4 in lower jaw and 4 in upper
jaw). Incisors are flat and help in biting the food.
Canines: On either side of the incisors are the canines. Canines are two in number in each jaw. Total number of canines in the mouth is 4.
(2 in lower jaw and 2 in upper jaw). They are sharp and meant for tearing the food.
Premolars: Premolars are behind the canines, and two in number on either side in each jaw. Total number of premolars in the mouth is 8.
( 4 in lower jaw and 4 in the upper jaw ). These teeth are used for grinding and crushing the food.
Molars: Molars are behind the premolars. In an adult, they are 6 in numbers in each jaw, three each on either side. Total number of
molars in the mouth is 12. (6 in lower jaw and 6 in upper jaw). These teeth are used for grinding and crushing the food.
Wisdom teeth: In young people, there are 8 molars in all. The second set of 4 molars appears at the age of 18 or even later. These are called
wisdom teeth.
Tooth decay: The bacteria present in the mouth break down the sugars present from the left over food and release acids which gradually
damage the teeth. This is called tooth decay.
Dental plaque: Saliva and bacteria present in the mouth stick to the teeth and form a sticky film which is called dental plaque.
Mastication: The process of chewing the food is called mastication.
Taste bud: The tongue has sense organs called the taste bud. These buds distinguish four basic tastes, salty, sour, sweet and bitter.
Salivary glands: There are 3 pairs of salivary glands in our mouth. A watery material called saliva is secreted by these glands. Saliva contains an
enzyme called amylase also called ptyalin, which changes starch into sugar called maltose.
Oesophagus: It is also called gullet. Food pipe
Liver : The reddish brown gland situated in the upper part of the abdomen on the right side which secretes bile is called liver. It is the
largest gland in the body. The bile secreted by the liver is stored in a sac called the gall bladder. Bile plays an important role in the
digestion of fats.
Gall bladder: The bile juice secreted by the liver is stored in a sac called the gall bladder.
Pancreas : Pancreas is a large cream coloured gland located just below the stomach. It secretes insulin. The pancreatic juice acts on
carbohydrates, fats and proteins and changes them into simpler forms.
Villi: ‘Villi’ is the plural of ‘villus’. The inner surface of the small intestine has a number of finger-like projections called villi. The function
of the villi is to increase the surface area for absorption of digested food.. Each villus has a network of thin and small blood
vessels close to its surface. The surface of the villi absorbs the digested food materials
Chewing cud: Grass-eating animals swallow the grass and latter they bring back the partially digested grass called cud from the rumen and
chew thoroughly. This is called chewing of the cud.
Rumination: The process of bringing back the partially digested cud from the rumen to the mouth and chewing it is called rumination. Or the
process of chewing cud is called rumination.
Rumen: In grass-eating animals, the swallowed grass is stored in a part of the stomach called rumen.
Cud: The partially digested grass in the rumen is called cud.
Ruminants: All animals who chew cud are called ruminants.
Extracellular digestation: Digestion outside cells in higher complex organisms because of presence of special organs (alimentary canals) is called
extracellular digestion.
Intracellular digestion: Digestion within cells in lower animals is called intracellular digestion. The food particles directly enter the cells and get digested.
Food vacuole: In amoeba the food is digested in the food vacuole.
Compound stomach: In ruminants the stomach has four chambers. They are rumen, reticulum, omasum and obomasum. Such a stomach is
called compound stomach.
Cellulose: Cellulose is a complex carbohydrate. It is also a tasteless white powdery material. It can be digested by ruminants only because
of the presence of certain bacteria and enzyme in their body. But that can not be digested by the humans because of the
absence of these bacteria and enzyme in human body to break it down. As a result, it is excreted out as such. Therefore, it does
not provide any energy to our body.
FILL IN THE BLANKS
- The inner lining of the stomach secretes mucous, hydrochloric acid and digestive juices.
- The mucous protects the lining of the stomach.
- Hydrochloric acid kills many bacteria that enter along with the food and makes the medium in the stomach acidic and helps the digestive juices to act.
- The small intestine is about 7.5 metres long.
- The small intestine receives secretions from the liver and the pancreas
- The pancreatic juice act on carbohydrates, facts and proteins.
- The intestinal juice break the carbohydrates into glucose, fats into fatty acids and glycerol and proteins into amino acids
- The shape of the stomach is a flattened U.
- Stomach is the widest part of the alimentary canal.
- The liver is a reddish brown gland situated in the upper part of the abdomen on the right side.
- Liver is the largest gland in the body.
- Liver secretes bile juice.
- Bile juice is stored in a sac called gallbladder.
- Bile plays a great role in the digestion of fats.
- Pancreas is a large cream coloured gland located just below the stomach.
- The inner walls of the small intestine have thousands of finger-like outgrowths or projections called villi
- The large intestine is about 1.5. metre in length.
- The function of the large intestine is to absorb water and some slats from the undigested food material.
- The ruminants have a large sac-like structure called Caecum between the small intestine and large intestine.
- Cellulose of the food is digested in the Caecum by the action of certain bacteria.
- The undigested food is excreted out through anus as faeces.
- In amoeba, ingestion of food takes place with the help of pseudopodia , and the food is digested in the food vacuole.
- The canal through which food passes is called food canal or alimentary canal.
- Mouth, mouth cavity, food pipe (oesophagus), stomach, small intestine, large intestine, rectum and anus makes alimentary canal.
- The alimentary canal along with the associated glands is called the digestive system.
- Digestion of food is brought about by special juices called enzymes.
- Grazing animals like cow and buffalos are called ruminants.
- The process of chewing cud is called rumination.
- The main function of teeth is to chew the food, and this process is called mastication.
- Saliva contains an enzyme called amylase or ptyalin.
- Saliva is secreted by the salivary glands in the mouth cavity.
- Number of molar teeth present in an human adult is 12. ( 6 in each jaw)
- The teeth which help in biting the food in humans are the incisors
- Food is digested by chemicals called enzymes
- Changing food to a usable simpler form is called digestion.
- The liver and pancreas are found near stomach.
- The longest part of the digestive tract in humans is the small intestine.
- Finger-like projections called villi are present in small intestine.
- The amylase (also called ptyalin) present in the saliva acts on starch and converts it to a sugar called maltose.
- Pepsin present in the Gastric juice in the stomach acts on proteins and converts it to peptides and amino acids.
PRIVATE BOOK QUESTIONS
STUDY QUESTIONS
I. Multiple Choice questions: Tick the correct answer.
1. Which of the following helps in the digestion of food ?
a) Nutrients b) Hormones c) Enzymes or juices d) Saliva
2. Saliva contains an enzyme called
a) Amylase b) Trypsin c) Pepsin d) None of these
3. The teeth adapted for flesh eating are
a) Incisors b) Premolars c) Canines d) Molars
4. Finger-like projections called villi are present in
a) Stomach b) Large intestine c) small intestine d) Liver
5. Most of digestion of food takes place in
a) Stomach b) Small intestine c) Large intestine d) Rectum
6. Absorption of food takes place in
a) Small intestine b) Pancreas c) Large intestine d) Liver
7. Absorption of water takes place in
a) Small intestine b) Large intestine c) Rectum d) Large intestine &rectum
II. Fill in the blanks
1. Saliva is secreted by the Salivary glands in the mouth cavity.
2. Number of molar teeth present in an human adult are 12.
3. The teeth which help in biting the food in humans are the incisors.
4. .Food is digested by chemicals called
5. Changing food to a usable simpler form is called digestion.
6. The liver and pancreas are found near the stomach..
7. The five steps in the process of nutrition are ingestion, digestion, absorption,
assimilation, egestion.
8. The largest gland in the human body is liver.
9. Amoeba digests its food in the food vacuole.
10. Taking in food from outside is called ingestion.
11. The longest part of the digestive tract in humans is the small intestine
12. Finger-like projections called villi are present in small intestine.
13. In amoeba pseudopodium are used for procuring food.
14. Absorption of food takes place through villi in the small intestine.
15. Number of molar teeth present in an human adult is 12. ( 6 in each jaw)
III. True or False
1. Canines are meant for tearing flesh. TRUE
2. Molar teeth are present in a human baby. FALSE
3. Mouth cavity is also known as food pipe. FALSE
4. Gastric juice is secreted by the small intestine. FALSE
5. Food is mostly digested by stomach. FALSE
6. In humans, there are 14 teeth in each jaw. FALSE
7. HCL is secreted in the stomach. TRUE
8. Deer is ruminant. TRUE.
9. Chewing of cud is shown by ruminants. TRUE
10. Food pipe is present in the neck TRUE
11. Tongue helps in mixing food with saliva. TRUE
IV. Match the column
Column A Column B
1. Amoeba Food vacuole
2. Cow Ruminant
3. Stomach HCL acid secreted
4. Liver Bile juice secretion
5. Small intestine Digestion completed
6. Large intestine Absorb water
7. Rectum storage of undigested food material
8. Salivary gland saliva
V. Define the following terms:
Answers are on first page
VI. Name the different organs of the digestive system.
1. Mouth and mouth cavity or buccal cavity
2. Oesophagus ( gullet or food pipe)
3. Stomach
4. Small intestine
5. Large intestine
6. Rectum
7. Anus
8. Salivary glands
9. Liver
10. Pancreas.
- Different types of teeth in an adult human being.
2. Canines 2 + 2 = 4 for tearing the food
3. Premolars 4 + 4 = 8 for grinding and crushing the food
4. Molars 6 + 6 =12 for grinding and crushing the food
- Three ruminant animals
- Largest gland in the human body : Liver
No.1. How is digestive system different from an alimentary canal?
Ans. Alimentary canal or digestive tract is a long, muscular and coiled tube which starts from the mouth and ends at anus. The different organs of the alimentary canal are :
1. Mouth and mouth cavity or buccal cavity
2. Oesophagus ( gullet or food pipe)
3. Stomach
4. Small intestine
5. Large intestine
6. Rectum
7. Anus
The alimentary canals and the associated glands such as salivary glands, liver and pancreas together constitute the digestive system.
No.2. Give the functions of different types of teeth in an adult human.
There are four different types of teeth in an adult human. They are
1. Incisors 4 + 4 = 8 for biting the food
2. Canines 2 + 2 = 4 for tearing the food
3. Premolars 4 + 4 = 8 for grinding and crushing the food
4. Molars 6 + 6 =12 for grinding and crushing the food
No.3. Describe the functions of the followings.
a) Saliva: Saliva is a watery material secreted by three pairs of salivary glands in our mouth. The function of saliva is to help in the digestion of food. It contains an enzyme called amylase (also called ptyalin) which acts on starch and changes the starch into a sugar called maltose.
b) Oesophagus: It is also called gullet or food pipe. It connects the mouth cavity with the stomach. It runs along the neck and the chest. No digestion takes place here. The function of the oesophagus is to help in pushing the food into stomach. Vomiting takes place when the food is not accepted by the stomach.
c) Tongue: Tongue is a muscular organ. The functions of the tongue are :
1) It helps in mixing the masticated food with saliva
2) It helps in swallowing down the food.
3) It tastes, as it bears taste buds.
4) It helps in speaking.
d) Liver: It is the largest gland of the body. The function of the liver is to secrete bile juice which helps in digestion of facts and is stored in a small bag called the gall bladder.
No.4. Explain the digestive systems in humans with the help of a diagram.
Ans. The Alimentary canal and the other associative glands together make the digestive system. The different parts of the alimentary canal are mouth ( buccal cavity), food pipe ( oesophagus ), stomach, small intestine, large intestine rectum and anus.
a) Mouth: The digestion starts in the mouth itself. The food is masticated with the help of different types of teeth. The masticated food gets mixed with saliva secreted by the salivary glands with the help of the tongue. Amylase or ptyalin, an enzyme present in the saliva acts on starch present in the food and converts it into a sugar called maltose. Then the food is swallowed down.
b) Food pipe: The food pipe or gullet is also called oesophagus. . It connects the mouth cavity with the stomach. The swallowed food passes to the stomach through oesophagus. Food is pushed down by the movement of the walls of the food pipe called peristalsis. movement.
c) Stomach: The stomach is a muscular bag lying in the upper abdomen. Here the food is churned and converted into a semi solid paste and mixes with gastric juice secreted in the stomach. The pepsin present in the gastric juice acts on the proteins and convert them into peptides and amino acids. This partially digested food then passes to the small intestine.
d) Small intestine: The small intestine is a long coiled tube. The intestinal juice digests all type of food and converts them to glucose, amino acids and fatty acids. These simpler substances are absorbed by villi present in the inner wall of the small intestine and passes to the circulatory system through the blood vessels. Digestion is completed here.
e) Large intestine; Large intestine has no digestive function to carry out. It helps in absorbing water and salt from the undigested food.
No.5. Is the large intestine really large?
Ans. No, the large intestine is not really large. It is smaller than the small intestine. The large intestine is about 1.5. meters long , while the small intestine is 6 metres long.
No.6. Where does digestion start in humans?
Ans. Digestion in human starts in mouth. The ingested food is masticated by the teeth and gets mixed with the saliva secreted by the salivary glands. From here the digestion starts.
No.7. Mention various steps in the process of digestion.
Ans. As q.no.4 above
No.8. Where is bile produced? Which component of food does it digest?
Ans. Bile is produced in liver, which is the largest gland of the body. The secreted bile is stored in a small bag called gall bladder. It digests fats.
No.9. Where are villi found and what is their function?
Ans. Villi are finger like projections or outgrowths found in the inner surface of the small intestine. The function of villi is to increase the surface area for absorption of digested food. Each villus has a network of thin and small blood vessels close to its surface. The surface of the villi absorbs the digested food materials which are transported via blood vessels to different organs of the body.
No.10. How does digestion take place in ruminant?
Ans. Ruminant has compound stomach. It has four chambers; rumen, reticulum, omasum and obomasum. The ingested food enters the first chamber called rumen. From rumen, the food enters the second chamber (reticulum). In these two chambers, the food is partially digested and converted into a soft pulp called the cud. In relax time the cud from the second chamber is brought back to the mouth and chewed thoroughly. This process of chewing cud is called rumination. During rumination, cud mixes with saliva and becomes a semi-liquid paste. From the mouth the semi-liquid paste food is pushed into the third chamber (omasum). From the third chamber (omasum), the food enters the fourth chamber (obomasum). In the fourth chamber, digestive juices are mixed with the semi-liquid food and digestion of food then starts. From the fourth chamber, the food enters the small intestine.
No.11. How is the nutrition in Amoeba different from that in human beings?
Ans. Amoeba is a microscopic, single-celled organism without having a mouth or a digestive system. It comes near its food and take in the food by means of false feet or pseudopodia. The food particle with a drop of water forms a food vacuole. The ingested food in the food vacuole is digested with the help of digestive juices (enzymes) produced within the body. The digestion in amoeba is intracellular. The digested food is then absorbed into the cell cytoplasm and the undigested food material is removed from the body at any point through a temporary vacuole.
Whereas, in case of human beings, the five steps of nutrition are ingestion, digestion, absorption, assimilation and egestion. Humans have special organs in their bodies for each of these steps. In case of humans, ingestion occurs in the mouth and the hands are used for this purpose.. The digestion in human beings is extracellular. The process of digestion starts in mouth. The masticated food gets mixed with saliva secreted by the salivary glands. Amylase or ptyalin , an enzyme present in the saliva acts on starch present in the food and convert it into a sugar called maltose. Then the food passes to the stomach through the oesophagus. In the stomach the food is churned and converted into a semi-solid paste and mixes with gastric juice secreted in the stomach. The pepsin present in the gastric juice acts on the proteins and convert them into peptides and amino acids. This partially digested food then passes to the small intestine. The intestinal juice digests all types of food and converts them to glucose, amino acids and fatty acids. These simpler substances are absorbed by villi present in the inner wall of small intestine and passes to circulatory system through blood vessels. The undigested food materials pass to the large intestine where water is absorbed. Then the undigested waste materials pass to the rectum and excreted out through anus as faeces.
NCERT BOOK
1. Fill in the blanks
a) The main steps of nutrition in humans are ingestion, digestion, absorption,
assimilation, egestion.
b) The largest gland in the human body is liver.
c) The stomach releases hydrochloric acid and digestive juices which act on food.
d) The inner wall of small intestine has many fingerlike out growth called villi.
e) Amoeba digests it food in the food vacuole.
2. True or False
a) Digestion of starch starts in mouth. TRUE
b) The tongue helps in mixing food with saliva. TRUE
c) The gall bladder temporarily stores bile. TRUE
d) The ruminants bring back the swallowed grass into their mouth and chew it for sometimes TRUE
3. Tick the correct answer.
a) Fat is completely digested in the
i) Stomach ii) mouth iii) small intestine iv) large intestine
b) Water from the undigested food is absorbed mainly in the
i) Stomach ii) food pipe iii) small intestine iv) large intestine
4. Match the column
Column A Column B
Food components products of digestion
Carbohydrates sugars
Proteins amino acids
Fats fatty acids and glycerol
5. What are villi? What is their location and function?
Ans. ‘Villi’ is the plural of ‘villus’. The inner surface of the small intestine has a number of finger-like projections or outgrowths called villi, The function of the villi is to increase the surface area for absorption of digested food.. Each villus has a network of thin and small blood vessels close to its surface. The surface of the villi absorbs the digested food materials.
6. Where is the bile produced? Which component of the food does it help to digest ?
Ans. The bile is produced in the liver, which is the largest gland of the body. It is reddish brown in colour and situated in the upper part of the abdomen on the right side. The bile secreted by the liver is stored in the gall bladder and received in the small intestine which helps in the digestion of fats.
7. Name the types of carbohydrates that can be digested by ruminants but not by humans. Give the reasons also.
Ans. Cellulose is a complex carbohydrate. It is also a tasteless white powdery material. It can be digested by ruminants only because of the presence of certain bacteria and enzyme in their body. But that can not be digested by the humans because of the absence of these bacteria and enzyme in human body to break it down. As a result, it is excreted out as such. Therefore, it does not provide any energy to our body.
8.. Why do we get instant energy from glucose?
Ans. Carbohydrates are the main source of energy. It is converted into glucose ( C6 H12 O6 ). Glucose is a typical carbohydrate which directly enters the blood stream and produces energy through respiration immediately. Therefore, we get instant energy from glucose.
9. Which part of the digestive canal is involved in :
i) Absorption of food : Small intestine
ii) Chewing of food : Buccal cavity
iii) Killing of bacterial : Stomach
iv) Complete digestion of food : Small intestine
v) Formation of faeces
10. Write one similarity and one difference between the nutrition in amoeba and human.
Ans. One similarity in nutrition between amoeba and humans is that there are five process of digestion in both organisms. (Ingestion, digestion, absorption, assimilation and egestion).
One difference in between amoeba and humans is that in humans digestion of food takes place in many parts but in amoeba digestion of food takes place in single cell.
11. Match the items of Column I with suitable items in Column II
Column I Column II
a) Salivary gland Saliva secretion
b) Stomach Acid release
c) Liver Bile juice secretion
d) Rectum storage of undigested food
e) Small intestine Digestion is completed
f) Large intestine Absorption of water
CHAPTER 2, NUTRITION IN ANIMALS
Textbook Exercise Solution
Q.1: Fill in the blanks:
(a) The main steps of digestion in humans are _________ and ___________.
(b) The largest gland in the human body is _________.
(c) The stomach releases hydrochloric acid and ______ juices which act on food.
(d) The inner wall of the smaller intestine has many finger-like outgrowths called _________.
(e) Amoeba digests its food in the ____________.
Ans: (a) buccal cavity, oesophagus, stomach, small intestine and large intestine (b) liver (c) digestive juices (d) villi (e) food vacuole.
Q.2: Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) Digestion of starch starts in the stomach.
(b) The tongue helps in mixing food with saliva.
(c) The gall bladder temporarily stores bile.
(d) The ruminants bring back swallowed grass into their mouth and chew it for sometime.
Ans: (a) F (b) T (c) T (d) T
Q.3: Choose the correct option:
(a) Fat is completely digested in the
(i) stomach (ii) mouth (iii) small intestine (iv) large intestine
(b) Water from the undigested food is absorbed in the
(i) stomach (ii) food pipe (iii) small intestine (iv) large intestine
Ans: (a) – (iii). (b) – (iv).
Q.4: What are villi ? What is their location and function ?
Ans: The inner wall of the small intestine has thousands finger-like outgrowths called villi.
These are found in small intestine. The villi increase the surface area for absorption of food.
Q.6: Where is the bile produced ? Which component of the food does it digest ?
Ans: Bile is produced in liver and is stored in a sac called the gall bladder.
The bile plays an important role in the digestion of fats.
Q.7: Name the type of carbohydrates that can be digested by ruminants but not by humans. Give the reasons also.
Ans: Cellulose is the carbohydrate that can be digested by ruminants. Ruminants have large sac like structure between the small intestine and large intestine. The cellulose of the food is digested by the action of certain bacteria which are not present in human beings.
Q.8: Why do we get instant energy from glucose ?
Ans: Because glucose easily breakdown in the cell with the help of oxygen and give carbon dioxide, water and energy.
Q.9: Which part of the digestive canal is involved in:
(i) absorption of food __________.
(ii) chewing of food __________.
(iii) killing of bacteria _________.
(iv) complete digestion of food ___________.
(v) formation of faeces ____________.
Ans: (i) small intestine. (ii) mouth. (iii) stomach (iv) small intestine. (v) large intestine.
Q.10: Write one similarity and one difference between the nutrition in amoeba and human beings.
Ans:
Similarity: During the digestion of food, in amoeba digestive juices are secreted into the food vacuole. They act on the food and break it into simpler substances. In human being, the inner walls of stomach and the small intestine also secrete the digestive juices. The digestive juices convert complex substances of food to simpler ones.
Difference: Amoeba feeds on some microscopic organisms. When it senses food, it pushes out pseudopodia around the food particle. The food is trapped in a food vacuole. Human beings take food through the mouth, digest and utilize it. The food is gradually digested as food travels through the various compartments.
Q.13: Can we survive only on raw, leafy vegetables / grass? Discuss.
Ans: We know that including all animals, fungi, many bacteria, non-green plants and human being do not possess the ability to synthesize their own food. Therefore depend upon autotrophs for their food supply either directly or indirectly. The green plants (leafy vegetables / grass) trap solar energy and manufacture their food in the form of glucose. So, leafy vegetables and grass can provide sufficient energy required for the survival of human being
SAMPLE QUESTIONS - ANSWERS
Q.1: What is mastication?
Ans: Mastication is a process in which chewing of food and mixing of saliva with it is done in mouth.
Q.2: What is the role of tongue in our mouth?
Ans: The tongue has following roles in our mouth:
=> It helps in talking.
=> It helps in mixing of saliva with the food during mastication.
=> It helps to swallow the food.
=> It gives us sensation of taste of food.
Q.3: What is peristalsis?
Ans: The powerful muscles in oesophagus gently push food down to the stomach in a wave - like action, calledperistalsis.
Q.4: What are secreted inside the stomach?
Ans: Gastric juice is secreted by the walls of stomach which contains HCl and Pepsin.
Q.5: What are the functions of HCl and Pepsin in stomach?
Ans: Functions of HCl:
=> It helps to kill the germs present in the food.
=> After mixing with the food it makes an acidic medium which is essential for the activation of pepsin enzyme
Functions of Pepsin:
=> Pepsin digests protein into peptides.
Q.6: Which enzyme is secreted in small intestine?
Ans: Maltase and Trypsin.
Q.7: What is secreted from liver?
Ans: Bile juice is secreted from liver.
Q.8: What is egestion?
Ans: The process by which the faecal matter is removed through the anus from time to time is called egestion.
Q.9: What is digestion?
Ans: Digestion is a process which include crushing of the food into smaller particles by chewing and then breakdown of its complex components into simpler substances with the help of enzymes in a liquid medium which can be absorbed by our body.
Q.10: Write short notes (1 or 2 sentences) on -
(a) Pancreas (b) Liver (c) Oesophagus (d) Remination or Rumination (e) Pseudopodia
Ans:
(a) Pancreas: Pancreas is a large cream coloured gland located or present just below the stomach. Pancreatic juice acts on carbohydrates and protein and changes them into simpler forms.
(b) Liver: Liver is a reddish brown gland present in the upper part of our abdomen on the right side. It is the largest gland in our body. It secretes bile juice stored in sac - like structure called gall bladder.
(c) Oesophagus: It is along, narrow, muscular tube which directly leads to the stomach. It is about 25 cm long and passes downwards through the neck, the thorax and the abdominal cavity.
(d) Rumination: A process in which partially digested food returns to the mouth in small lumps and the animal chews it. This type of process is called Remination or Rumination and such types of animals are calledRuminants.
(e) Pseudopodia: The unicellular organism like amoeba constantly changes its shape and position. It catches food by pushing out a finger - like projection called Pseudopodia.
Q.11: What are digestive enzymes?
Ans: There are different types of enzymes which are used for the digestion of different food materials like - carbohydrates, fats, protein etc. The process of digestion involves the association of several catalytic organic compounds. These are amylase, pepsin, lipase, tripsin etc. These organic compounds are known as digestive enzymes
Textbook Exercise Solution
Q.1: Fill in the blanks:
(a) The main steps of digestion in humans are _________ and ___________.
(b) The largest gland in the human body is _________.
(c) The stomach releases hydrochloric acid and ______ juices which act on food.
(d) The inner wall of the smaller intestine has many finger-like outgrowths called _________.
(e) Amoeba digests its food in the ____________.
Ans: (a) buccal cavity, oesophagus, stomach, small intestine and large intestine (b) liver (c) digestive juices (d) villi (e) food vacuole.
Q.2: Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) Digestion of starch starts in the stomach.
(b) The tongue helps in mixing food with saliva.
(c) The gall bladder temporarily stores bile.
(d) The ruminants bring back swallowed grass into their mouth and chew it for sometime.
Ans: (a) F (b) T (c) T (d) T
Q.3: Choose the correct option:
(a) Fat is completely digested in the
(i) stomach (ii) mouth (iii) small intestine (iv) large intestine
(b) Water from the undigested food is absorbed in the
(i) stomach (ii) food pipe (iii) small intestine (iv) large intestine
Ans: (a) – (iii). (b) – (iv).
Q.4: What are villi ? What is their location and function ?
Ans: The inner wall of the small intestine has thousands finger-like outgrowths called villi.
These are found in small intestine. The villi increase the surface area for absorption of food.
Q.6: Where is the bile produced ? Which component of the food does it digest ?
Ans: Bile is produced in liver and is stored in a sac called the gall bladder.
The bile plays an important role in the digestion of fats.
Q.7: Name the type of carbohydrates that can be digested by ruminants but not by humans. Give the reasons also.
Ans: Cellulose is the carbohydrate that can be digested by ruminants. Ruminants have large sac like structure between the small intestine and large intestine. The cellulose of the food is digested by the action of certain bacteria which are not present in human beings.
Q.8: Why do we get instant energy from glucose ?
Ans: Because glucose easily breakdown in the cell with the help of oxygen and give carbon dioxide, water and energy.
Q.9: Which part of the digestive canal is involved in:
(i) absorption of food __________.
(ii) chewing of food __________.
(iii) killing of bacteria _________.
(iv) complete digestion of food ___________.
(v) formation of faeces ____________.
Ans: (i) small intestine. (ii) mouth. (iii) stomach (iv) small intestine. (v) large intestine.
Q.10: Write one similarity and one difference between the nutrition in amoeba and human beings.
Ans:
Similarity: During the digestion of food, in amoeba digestive juices are secreted into the food vacuole. They act on the food and break it into simpler substances. In human being, the inner walls of stomach and the small intestine also secrete the digestive juices. The digestive juices convert complex substances of food to simpler ones.
Difference: Amoeba feeds on some microscopic organisms. When it senses food, it pushes out pseudopodia around the food particle. The food is trapped in a food vacuole. Human beings take food through the mouth, digest and utilize it. The food is gradually digested as food travels through the various compartments.
Q.13: Can we survive only on raw, leafy vegetables / grass? Discuss.
Ans: We know that including all animals, fungi, many bacteria, non-green plants and human being do not possess the ability to synthesize their own food. Therefore depend upon autotrophs for their food supply either directly or indirectly. The green plants (leafy vegetables / grass) trap solar energy and manufacture their food in the form of glucose. So, leafy vegetables and grass can provide sufficient energy required for the survival of human being
SAMPLE QUESTIONS - ANSWERS
Q.1: What is mastication?
Ans: Mastication is a process in which chewing of food and mixing of saliva with it is done in mouth.
Q.2: What is the role of tongue in our mouth?
Ans: The tongue has following roles in our mouth:
=> It helps in talking.
=> It helps in mixing of saliva with the food during mastication.
=> It helps to swallow the food.
=> It gives us sensation of taste of food.
Q.3: What is peristalsis?
Ans: The powerful muscles in oesophagus gently push food down to the stomach in a wave - like action, calledperistalsis.
Q.4: What are secreted inside the stomach?
Ans: Gastric juice is secreted by the walls of stomach which contains HCl and Pepsin.
Q.5: What are the functions of HCl and Pepsin in stomach?
Ans: Functions of HCl:
=> It helps to kill the germs present in the food.
=> After mixing with the food it makes an acidic medium which is essential for the activation of pepsin enzyme
Functions of Pepsin:
=> Pepsin digests protein into peptides.
Q.6: Which enzyme is secreted in small intestine?
Ans: Maltase and Trypsin.
Q.7: What is secreted from liver?
Ans: Bile juice is secreted from liver.
Q.8: What is egestion?
Ans: The process by which the faecal matter is removed through the anus from time to time is called egestion.
Q.9: What is digestion?
Ans: Digestion is a process which include crushing of the food into smaller particles by chewing and then breakdown of its complex components into simpler substances with the help of enzymes in a liquid medium which can be absorbed by our body.
Q.10: Write short notes (1 or 2 sentences) on -
(a) Pancreas (b) Liver (c) Oesophagus (d) Remination or Rumination (e) Pseudopodia
Ans:
(a) Pancreas: Pancreas is a large cream coloured gland located or present just below the stomach. Pancreatic juice acts on carbohydrates and protein and changes them into simpler forms.
(b) Liver: Liver is a reddish brown gland present in the upper part of our abdomen on the right side. It is the largest gland in our body. It secretes bile juice stored in sac - like structure called gall bladder.
(c) Oesophagus: It is along, narrow, muscular tube which directly leads to the stomach. It is about 25 cm long and passes downwards through the neck, the thorax and the abdominal cavity.
(d) Rumination: A process in which partially digested food returns to the mouth in small lumps and the animal chews it. This type of process is called Remination or Rumination and such types of animals are calledRuminants.
(e) Pseudopodia: The unicellular organism like amoeba constantly changes its shape and position. It catches food by pushing out a finger - like projection called Pseudopodia.
Q.11: What are digestive enzymes?
Ans: There are different types of enzymes which are used for the digestion of different food materials like - carbohydrates, fats, protein etc. The process of digestion involves the association of several catalytic organic compounds. These are amylase, pepsin, lipase, tripsin etc. These organic compounds are known as digestive enzymes