Write down digestion in mouth in …

Digestion of food occurs in the following steps:

1. Mouth (Buccal cavity): The mouth contains teeth, which crush the food into small particles. Salivary glands present in the mouth secrete saliva, which moistens the food. It also contains enzyme salivary amylase which gets mix with food and form bolus. From here, food travels to the esophagus or swallowing tube. The esophagus is a muscular tube extending from the pharynx to the stomach. 
2. Stomach- The stomach is a sac-like organ with strong muscular walls which acts like mixer and grinder. Gastric glands are present in the wall of the stomach which release following secretions:
   1. Hydrochloric acid To make the medium acidic for the action of enzyme pepsin.
   2. Mucus To protect the inner lining of the stomach from the action of an acid.
   3. Pepsin A protein-digesting enzyme.
3. Small intestine is made up of three segments, the duodenum, jejunum, and ileum.  The small intestine is a long tube loosely coiled in the abdomen It is the site of complete digestion of carbohydrates, proteins, and fats. It receives secretions from liver and pancreas.
   1. Bile juice It is secreted by the liver and performs the following functions:
      It makes the medium alkaline for the pancreatic enzymes to act. It also breaks down large fat globules into smaller globules.
   2. Pancreatic juice It is secreted by the pancreas. It contains enzymes like amylase for digesting starch, trypsin for digesting proteins and lipase for breaking down emulsified fats.
   3. Intestinal juice It is secreted by the walls of the small intestine. It contains a number of enzymes such as maltase, lipase etc., for complete digestion

Colon - The final stage of the digestive system is the colon (large intestine) which absorbs water and salts before the remains are passed out of the rectum as faeces. The colon can also help to absorb remaining carbohydrate and some fats.