The major purpose of the small intestine is digestion and absorption of nutrients. In the small intestine, enzymes (produced by the salivary glands in the mouth, in the pancreas and in the intestinal cells) break down nutrients such as carbohydrates, proteins or fats into their building blocks.
For example, proteins, peptides and amino acids are acted upon by enzymes such as trypsin and chymotrypsin, which are produced by the pancreas. Pancreas also produced lipases and this enzyme break-up triglycerides into free fatty acids and monoglycerides.
The intestinal cells assume the roles of absorbing the building blocks (for example sugar, amino acids or fatty acids) together with vitamins, salts and water which pass into the bloodstream to be used by the body.
The small intestinal cells also produce countless intestinal hormones. These hormones associated and stimulus the production of bile or pancreatic juice. For example, enzymes will enter the small intestine in response to the hormone cholecystokinin, which is produced in response to the presence of nutrients.
The other hormone, secretin activate bicarbonate to be released into the small intestine from the pancreas to neutralize the potentially harmful acid coming from the stomach.
Small intestines – Main functions
