Digestion is physical and enzymatic breakdown of large complex organic substances e.g carbohydrate, and fats into simple soluble and diffusible and absorbable form like glucose, amino acid and fatty acid which can be use in metabolism. The alimentary canal is a continuous muscular tube running from the buccal cavity to the anus. It is limited anteriorily by the lips which help to pass food to the mouth and prevent the food from falling during oneing action.The buccal cavity is a region enclosing the jaws the tongue and it is lined by squaimous epithelium. The mouth contain teeth of different kind which carry out the process of mastication( physical digestion). The root of the mouth is a hard palatic which continuous to the pharynx to form a soft palate. The tongue has many taste buds. The tongue moves food around the mouth and mixes and moist it with saliva. The mouth increases saliva secretion and the food is swallow into bolus under peristalses action.

                                                           The main function of the alimentary canal are;

Ingestion it simply means the taking in a food.

Peristalses the movement of food along the alimentary canal

Digestion the breakdown of ingested food into simple, soluble, absorbable.

Absorption the passage of these simple soluble molecules into the blood and lymph.

Assimilation The use of the absorbed food by the cells of the body.

Egestion or defecation This is the removal of undigested food material, bacteria and death cells from the body.

(diagram of the alimentary canal)