NCERT Class 11-Biology: Chapter –16 Digestion and Absorption Part 3

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Question 8:

Does gall bladder make bile?

Answer:

No, gall bladder doesn’t produce bile. Gall bladder stores and concentrates bile.

The bile is secreted by the hepatic cells.

Question 9:

Correct the following statements by deleting one of entries (given in bold).

a. Goblet cells are located in the intestinal mucosal epithelium and secrete chymotrypsin / mucus.

b. Fats are broken down into di- and monoglycerides with the help of amylase/ lipases.

c. Gastric glands of stomach mucosa have oxyntic cell / chief cells which secrete HCl.

d. Saliva contains enzymes that digest starch /protein.

Answer:

(a) Goblet cells are located in the intestinal mucosal epithelium and secrete mucus.

(b) Fats are broken down into di- and monoglycerides with the help of lipases.

(c) Gastric glands of stomach mucosa have oxyntic cell which secrete HCl.

(d) Saliva contains enzymes that digest starch.

Short Answer Type Questions

Question 1:

What is pancreas? Mention the major secretions of pancreas that are helpful in digestion.

Answer:

Pancreas is a compound elongated organ situated between the limbs of the ‘U’ shaped duodenum.

The exocrine portion secretes an alkaline pancreatic juice containing enzymes and the endocrine portion secretes hormones, insulin and glucagon.

These secretions are major and are helpful in digestion.

Question 2:

Name the part of the alimentary canal where major absorption of digested food takes place. What are the absorbed forms of different kinds of food materials?

Answer:

The part of the alimentary canal where major absorption of the digested food takes place is small intestine.

The Biomacromolecules of food are converted into simple substances in duodenum region of the small intestine.

The simple substances thus formed are absorbed in the jejunum and ileum regions of the small intestine.

Small intestine has small finger like folding called Villi. Villi produce numerous microscopic projections called microvilli.

Microvilli increase the surface area enormously.

Villi are supplied with a network of capillaries and a large lymph vessel called the lacteal.

In small intestine the carbohydrates is absorbed in the form of glucose, proteins are absorbed in the form of amino acids and fats are absorbed in the form of fatty acids and glycerol.

So the absorbed forms of different kinds of food materials are amino acids, monosaccharide, fatty acids and glycerol.

Question 3:

List the organs of human alimentary canal and name the major digestive glands with their location.

Answer:

The human alimentary canal begins with mouth (anterior opening) followed by buccal cavity or oral cavity. The oral cavity then leads into short pharynx followed by oesophagus and stomach. Stomach is followed by small intestine and large intestine. And the alimentary canal opens posteriory through the anus.

The major digestive glands associated with the alimentary canal with their location are as follows:

- Salivary glands: is present in the mouth. The saliva is produced by three pairs of salivary glands namely parotids (cheek), the sub-maxillary / sub-mandibular (lower jaw) and the sublingual’s (below the tongue).

- Gastric glands: is present in stomach

- Liver: is situated adjacent to the stomach. It is located in abdominal cavity just below the diaphragm.

- Pancreas: is situated below the stomach. It is located between the limbs of the ‘C’-shaped duodenum.

Question 4:

What is the role of gall bladder? What may happen if it stops functioning or is removed?

Answer:

The role of gall bladder is that is stores and concentrates bile juice secreted by liver. The gall bladder releases the bile juice as and when required in the duodenum.

Gall bladder is thin muscular sac.

If the gall bladder stops functioning or is removed there won’t be any problem in the digestive system or digestive functioning.

If the gall bladder is removed or if it stops functioning, the bile juice will directly move to the small intestine. But as earlier it won’t concentrate but later the body learns to adjust with the changes.

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