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Introduction and functional organization of Human Digestive System

The gastro-Intestinal Tract (GIT) is designed to provide nutrition to the body. It forms the gate through which nutritive substances enter in the body, they are digested, nutrients are absorbed and unusable substances are removed from the body. It is a tubular structure open at both the ends. Total length of GIT is about 10 meters (30 feet in adults). Food enters from mouth it is chewed and mixed with saliva. It passes into the pharynx, then into the oesophagus which is 25 cm long. The peristaltic movements move the food in stomach.

From the stomach food passes into… (157 more words) …

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Immune System of GIT

GIT is connected to the exterior at both the ends the mouth and the anal opening. Thus it makes a channel through which organisms can enter inside. The invading organisms are destroyed by immune system, it includes;

  • Peyer’s patches; these are aggregations of lymphoid tissue in the submucosa.

  • Diffuse population of immune cells; these cells are called immunocytes. They are present in the mucosa and submucosa throughout the GIT. These cells are T and B lymphocytes, plasma cells, mast cells and macrophages they secrete antibodies locally in response to antigens that enter in GIT.

  • Mesenteric lymph nodes

Functions:

Food… (65 more words) …

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