(a) Draw a diagram of human alimentary canal and label the following parts:
(i) largest gland.
(ii) gland that secretes digestive enzymes and hormone.
(iii) Part where HCl is produced.
(iv) part where digested food is absorbed.
(b) What are villi? Explain their function in the digestive system.

Explanation

(i) Largest gland- Liver
(ii) Gland that secretes digestive enzymes and hormone-Pancreas
(iii) Part where HCl is produced-stomach
(iv) Part where digested food is absorbed-Small intestine

(b) The small intestine is especially adapted for absorption of digested food. The inner surface of small intestine has millions of tiny, finger like projections called villi which provide the inner walls of small intestine a very large surface area. The large surface area helps in the rapid absorption of digested food. The villi are richly supplied with blood vessels which take the absorbed food to each and every cell of the body.