General Science 6th Class Chapter 4 Human Digestive System Solved Exercise

General Science

6th Class

Chapter 4

Human Digestive System

Questions

4.1 Encircle the correct option.

1. A part of the digestive system which is not in correct with food is:

a. small intestine        b. stomach        c. liver        d. large intestine

2. In humans, most of digestion takes place in:

a. mouth        b. oesophagus        c. stomach        d. small intestine

3. Saliva is produced in:

a. oral cavity        b. oesophagus        c. stomach        d. small intestine

4. The food digested by the enzyme "sucrase" belongs to nutrients group:

a. carbohydrates        b. fats        c. oils        d. proteins

5. The muscular tube leading from oral cavity to stomach:

a. small intestine        b. large intestine        c. oesophagus        d. bile duct

6. Germs present in food are killed in stomach by:

a. hydrochloric acid        b. citric acid        c. carbonic acid        d. none of these

7. Digestive enzymes convert starch into:

a. fatty acids        b. vitamins        c. minerals        d. simple sugar

8. Proteins are digested into:

a. fatty acids        b. amino acids        c. glycerol        d. glucose

9. Digested food is absorbed into blood through the walls of:

a. villi        b. large intestine        c. stomach        d. bile duct

10. Water and salts from indigested food are absorbed into blood through walls of:

a. small intestine        b. large intestine        c. villi        d. gallbladder

4.3 Give short answer.

1. Define digestion.

Ans.

The process during which large and complex molecules are broken down into such smaller pieces which pass across walls of small intestine and absorb into the blood is called digestion.

2. How is chewing important in human digestive system?

Ans.

Chewing activity mixes saliva in the food to make it soft.

3. Name the liquid which is secreted by salivary glands.

Ans.

Salivary glands secrete saliva.

4. Describe the role of oesophagus in human digestive system.

Ans.

Oesophagus is a narrow muscular tube through which food passes from oral cavity to the stomach.

5. Why do carbohydrates, fats and proteins need to be broken down into smaller molecules?

Ans.

The food we eat consist of large and complex molecules of carbohydrates, fats and proteins, these complex food molecules cannot pass across wall of small intestine for absorption in blood.

6. What are the products of digestion of carbohydrates, proteins and fats?

Ans.

Carbohydrates from glucose, protein gives amino acids and fats release fatty acid and glycerol.

7. What structures secrete enzymes necessary for digestion in man?

Ans.

Salivary glands, gastric glands, liver and pancreas are structures secrete enzymes necessary for digestion in man.

8. How are villi important for absorption?

Ans.

The digested food is absorbed through the wall of villi and passes into the blood streams.

9. How is large intestine important in digestive system of man?

Ans.

Some water and mineral salts are also absorbed into the blood through the walls of the large intestine.

10. Write the functions of gall bladder.

Ans.

Gall bladder stores bile.