Question

(a) Name the main organs of the human digestive system. Also name the associated glands.
(b) How do carbohydrates, fats and proteins get digested in human beings?

Answer 1

(a) The main organs of human digestive system are mouth, oesophagus, stomach, small intestine, large intestine and anus. The associated glands are salivary glands, liver and pancreas.

(b) Carbohydrates are digested by the enzyme, salivary amylase, present in the saliva. As food enters the mouth cavity, it gets mixed with the saliva, which contains salivary amylase. This enzyme helps in the digestion of starch.
The enzyme, pancreatic amylase, is secreted by the pancreas. This enzyme reaches the small intestine and digests the carbohydrates.
Proteins are digested by the enzyme, pepsin, that is secreted in the stomach by the glands presents in its walls. Trypsin is secreted by the pancreas. This enzyme reaches the small intestine and digests the proteins.
Fats are digested by the enzyme, lipase, that is secreted by the pancreas and the bile juice that is secreted by the liver. These two act on the fats in the small intestine.