Digestive system

DIGESTIVE SYSTEM:

Digestion is a process of breaking down complex molecules into simple molecules.It includes a set of digestive organs which work together to break down the food or complex molecules into simpler molecules from which energy can be assimilated.It involves 5 steps INGESTION,DIGESTION,ABSORPTION,ASSIMILATION and EGESTION. DIGESTIVE ORGANS:

Digestive organs are of two types depending on their involvement in the process of digestion,they are alimentary organs or tract and accessory organs. Alimentary tract is made up of BUCCAL CAVITY,PHARYNX,ESOPHAGUS,STOMACH,SMALL INTESTINE AND LARGE INTESTINE. These organs are directly involved in the process of digestion. ACCESSORY ORGANS are the organs that helps in digestion but are not a part of digestive tract.These include SALIVARY GLANDS, PANCREAS,LIVER and GALLBLADDER.These accessory organs release secretions which add on to the process of digestion.

PROCESS OF DIGESTION:

The process of digestion starts in the mouth itself.Food is taken into the body through mouth,with the help of teeth it is chewed and broken into smaller pieces. Tongue is present in the inferior part of the mouth which helps in pushing the food for swallowing. It also contain taste buds for tasting the food. The salivary glands present in the mouth secretes saliva which convert starch into sugars.This shows that the process of digestion begins in the mouth only. The food then passes into esophagus, in esophagus there is no digestion taking place.The mucus lining of the esophagus helps in pushing the food downwards.The food then passes into stomach from esophagus.Stomach is a muscular organ located on the left side of the abdominal cavity. In stomach several juices are released like hydrochloric acid, digestive juices which continue the process of digestion.From stomach food is passed into small intestine. Small intestine is long,coiled which contain villi that helps in absorption of food.By the time food leaves small intestine 97% of digestion is completed. LIVER secrets bile juice which is stored in GALLBLADDER. the bile is released into the small intestine along with the pancreatic juice released by the PANCREAS.From SMALL INTESTINE food is absorbed by several organs. The remaining food is passed into LARGE INTESTINE where water is reabsorbed. The left out food is stored in RECTUM as faeces and is EJECTED out through ANUS.