Digestion of food occurs in following ways in:
(i) Mouth (Buccal cavity): The mouth contains teeth, which crushes the food into small particles. Salivary glands present in the mouth secretes saliva which moistens the food. It also contains enzyme salivary amylase, that acts as
(ii) Stomach: It serves as a muscular bag which is situated towards the left side of the abdominal cavity, beneath the diaphragm.
- Mucous: It is an aqueous secretion produced by the mucous membranes. It functions by protecting the stomach lining and gastric pits from the acid which is produced by the glands to destroy the bacteria that entered along with the food particles.
- Digestive enzymes: They are the group of enzymes which functions by breaking down polymeric macromolecules like biopolymers into their smaller and simpler substances.
- Hydrochloric acid: It is the digestive fluid formed by the stomach during the process of digestion. It functions by destroying harmful microorganisms present in the food particles.
(iii) Small Intestine: It is the site of complete digestion of carbohydrates, proteins and fats.
It receives secretions from liver and pancreas.
- Bile juice It is secreted by liver and performs the following functions :
It makes the medium alkaline for the pancreatic enzymes to act and also breaks down large fat globules into smaller globules.
- Pancreatic juice It is secreted by pancreas. Contains enzymes like amylase for digesting starch, trypsin for digesting proteins and lipase for breaking down emulsified fats.
