Question

Explain the general functions of the digestive system.

Describe how the products of carbohydrate, protein, and fat digestion are absorbed from the alimentary canal into the body.

Answer 1

The general functions of digestive system are ingestion of food, secretion of fluids and digestive enzymes, mixing and movement of food and wastes through the body, digestion of food into smaller pieces, absorption of nutrients and excretion of wastes.

Carbohydrate digestion starts in mouth by enzyme amylase present in the saliva and when food enters into stomach, the complex protein is digested into the simple protein of dipeptides by pepsin. In small intestine food is further digested in the presence of pancreatic juice and bile. Dipeptides are converted into the amino acids by trypsin and lipids are emulsified and digested by lipase and bile.

The absorption of carbohydrate ie, the broken down simplest sugar molecules are absorbed through the small intestine walls into the bloodstream and used by the body as fuel or sent for storage in the liver for use at a later time. Fibers are which are indigestible passes through the digestive tract essentially undigested.

The absorption of proteins are  as aminoids, absorbed through the wall of the small intestine into the bloodstream and distributed throughout the body to repair injuries and replace dying cells.

For the absorption of fat ,bile breaks up conglomerations of fat in the digestive tract into smaller emulsified particles by lipase, a fat-digesting enzyme which can break it down. These broken down fat particles like fatty acids and cholesterol are then absorbed through the intestinal walls into the bloodstream.

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