Question

State one role of each of the following in human digestive system :
(i) Hydrochloric acid
(ii) Villi
(iii) Anal Sphincter
(iv) Lipase

Answer 1

Part (i): Hydrochloric Acid:
Hydrochloric acid (HCl) in the stomach plays a crucial role in creating an acidic environment that aids in the digestion of food. It activates the enzyme pepsinogen into pepsin, which breaks down proteins. HCl also helps in killing harmful bacteria that might enter the stomach with food.

Part (ii): Villi:
Villi are tiny hair-like projections present in the inner lining of the small intestine. Their main role is to increase the surface area for absorption of nutrients like amino acids, fatty acids, and glucose from digested food into the bloodstream.

Part (iii): Anal Sphincter:
The anal sphincter is a muscular ring at the end of the rectum. It plays a key role in controlling the release of feces from the body. It relaxes to allow the passage of stool and contracts to retain it until appropriate time for defecation.

Part (iv): Lipase:
Lipase is an enzyme that helps in the digestion of fats. It is produced in the pancreas and acts in the small intestine, where it breaks down fats into fatty acids and glycerol, making it easier for the body to absorb them.