Question

Explain how the human alimentary canal is adapted to perform its functions.

Answer 1

1. The mouth has different types of teeth; that chew food increasing surface area for enzyme action;.
2. The mouth has salivary glands; that secrete saliva which lubricates and softens food; Salivary amylase breaks down starch into maltose;
3. The tongue rolls food into boluses; and pushes them to the back of the mouth for swallowing.
4. The esophagus is hollow for easy swallowing of food; it has muscles that contract and relax; to move food boluses through peristalsis
5. The alimentary canal is long; to provide a large surface area for digestion and absorption of food;
6. Small intestine is highly coiled; offering a large surface area for digestion and absorption of food;
7. the inner lining of the ileum has villi and micro-villi which increase surface area for absorption
8. Doudenum has openings of duct; through which pancreatic juice and bile get into the lumen;
9. The alimentary canal has goblet cells that secrets mucus; for lubrication of food; and protection of the wall from digestive enzymes;
10. The Brunner’s glands also secretes an alkaline fluid ;which provide an optimum pH for action of intestinal enzymes;Small intestines has intestinal glands; that secrete digestive enzymes;
11. the ileum has a rich network of blood capillaries that supply oxygen and remove metabolic waste from the intestinal tissues; and transports digested food and other nutrients
12. The walls have circular and longitudinal muscles; whose peristaltic contractions causes movement of food in the gut; and mixing of food with digestive enzymes;
13. The ileum has a thin epithelium; that allows soluble food materials to pass through rapidly into the bloodstream
14. The villi has lacteal; to transport absorbed lipids
15. The colon has a wide lumen; to increase surface area for absorption of water and mineral salts
16. The anus has anal sphincter muscles; that relax and contract to eliminate the indigestible and undigestible materials;