Digestion is the process of break down of complex food substance into simple molecules. Digestion is carried out by our digestive system by mechanical and biochemical method. The digestive system consists of alimentary canal and the associate glands.
The process of digestion is accomplished by mechanical and chemical processes. The buccal cavity performs two major functions mastication of food and facilitation of swallowing. The teeth and the tongue with the help of saliva masticate and mix up the food thoroughly. Salivary glands secrete saliva which contains an enzyme called the salivary amylase. This enzyme breaks down starch content and moistens the food, before the tongue and other muscles push the food into the pharynx.
The pharynx passes the chewed food from the mouth to the esophagus. The flap of tissue known as the epiglottis present in pharynx prevents food from entering into the wind pipe. The esophagus is a muscular tube connecting the pharynx to the stomach. It carries swallowed masses of chewed food along its length and pushes it down to the stomach.
The stomach is a sac-like organ in which food is further digested both mechanically and chemically. Enzymes and acid is released by stomach. The main enzyme is pepsin, which chemically digests protein. The stomach stores the partly digested food until the small intestine is ready to receive it. When the small intestine is empty, a sphincter opens to allow the partially digested food to enter the small intestine.
The stomach stores the partly digested food until the small intestine is ready to receive it. When the small intestine is empty, a sphincter opens to allow the partially digested food to enter the small intestine. Following are the enzyme are released in the small intestine:
| Amylase | Made in pancreas and it digest carbohydrate |
| Tryspin | Pancreas, digest protein |
| Lipase | Pancreas, duodenum , digest lipids |
| Maltase | Duodenum , digest carbohydrate |
| Peptidase | Duodenum, digest proteins |
The jejunum is the second part of the small intestine, where most nutrients are absorbed into the blood. The mucous membrane lining the jejunum is covered with millions of microscopic, fingerlike projections called villi (singular, villus). Villi increases surface area for absorption. 
The large intestine is a relatively wide tube that connects the small intestine with the anus. Like the small intestine, the large intestine also consists of three parts: the cecum (or caecum), colon, and rectum. Here food absorption takes place and undigested food is excreted out from anus.
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