Describe the alimentary canal of man.
Mouth: Helps in intake of whole food. Teeth: Helps in chewing and grinding of food. Tongue: Helps in tasting food + rolling food + swallowing food. Salivary glands: Secrete saliva and mucus. The enzyme called salivary amylase is present in saliva which breaks down the complex starch into sugar. Oesophagus (food pipe): Food moves towards stomach through oesophagus by rhythmic contraction of its muscles called as peristaltic movements or peristalsis. Stomach: Muscular walls of stomach help in mixing food thoroughly with digestive juices. Stomach has gastric glands which secrete gastric juice containing pepsin for digestion of proteins, hydrochloric acid for creating acidic medium and mucus to protect inner lining of stomach from acid. Small Intestine: Digestive juices like pancreatic juice, bile juice and the intestinal juices are secreted in the small intestine to help to complete the process of digestion. After digestion, the nutrients are absorbed by the villi present in the walls of the small intestine.
