Human Digestive System

DIGESTIVE SYSTEM

It is the group of organs working together to convert food into energy and basic nutrients and other things which is important for the human body and provide energy to the entire human body. Food passes through the long tube inside the human body known as alimentary canal or GI track (Gastrointestinal tract). Thealimentary canal consists of oral cavity, pharynx, esophagus, stomach, small intestine and large intestine. In addition, there are several parts of body which help the body in digestion of food.

Organs

Oral Cavity

• Teeth

Function:  Mastication (cutting and grinding of food) & communication.

Secretion:  None.

• Lips and cheeks

Function: Manipulation of food; hold food in position between the teeth; communication.

Secretion: saliva from buccal glands(mucus only).

• Tongue

Function: Manipulation of food; hold food in position between the teeth; cleansing teeth; taste.

Secretion: Some mucus; small amount of serous fluid.

Salivary Glands

• Parotid gland

Function Secretion of saliva through ducts to posterior portions of oral cavity.

Secretion: Saliva with amylase.

• Submandibular glands

Function: Secretion of saliva in floor of oral cavity.

Secretion: Saliva with amylase& mucus.

• Sublingual Glands: Saliva with mucus only.

Function: Secretion of saliva in floor of oral cavity.

Secretion: Saliva with mucus only.

Pharynx

Function: swallowing.

Secretion: some mucus.

Esophagus

Function: Movement of food by peristalsis from pharynx to stomach.

Secretion: Mucus.

Stomach

Function: Mechanical mixing of food; enzymatic digestion; absorption; storage.

• Mucous cells

Function: Protection of stomach wall by mucus production.

Secretion: Mucus.

• Parietal cells

Function: Decrease in stomach PH.

Secretion: HCl (Hydrochloric acid).

• Zymogen cells

Function: Protein digestion.

Secretion: Pepsinogen.

• Endocrine cells

Function: Regulation of secretion and motility.

Secretion: Gastrin.

Small intestine

• Goblet cell

Function: Protection

Secretion: Mucus

• Endocrine cell

Function: Regulation of secretion and motility.

Secretion: Lipase, Gastrin, Lactase, secretin.

• Duodenal glands

Function: protection

Secretion: Mucus

• Absorptive cells

Function: Secretion of digestive enzymes and absorption of digestive materials.

Secretion: Maltase, peptidases, amylase and Enterokinase.

Large intestine

• Goblet cells

Function: Food movement, storage, Absorption and storage.

Secretion: Mucus.

Accessory Glands

• Liver

Function: Secretion of bile into duodenum

Secretion: Bile

• Gall bladder

Function: Bile storage; electrolytes to concentrate bile and absorb water.

Secretion:No secretion of its own, stores and concentrates bile.

• Pancreas

Function: Enzymes and bicarbonate ions into duodenum.

Anus

Function: The hole through which all the waste thrown out.

Secretion: It secrets all the waste material of food.