Question

Think of a meal…Describe how each major class of nutrients is chemically digested and absorbed. Where does the chemical digestion of starch (carbohydrates) take place? Where does the chemical digestion of proteins take place? Where does the chemical digestion of lipids take place? Don't forget to include contact digestion at the enterocyte microvilli. What happens to the fiber? What is a chylomicron?

Answer 1

Digestion of carbohydrates :

Digestion of carbohydrates begins in mouth by the enzyme salivary amylase. And primary digestion starts at small intestine by the enzymes secreted by pancreas like (alpha - amylase) , ( alpha- glucosidase ).

Digestion of proteins :

Digestion begins in stomach by the release of pepsin and later in duodenum by the enzymes like trypsin and chymotripsin by pancreas. Breaking down of proteins into polypeptides into exopeptides and dipeptides which are converted to amino acids.

Digestion of lipids:

Digestion of lipids begins in the mouth. The salivary glands secrete the digestive enzyme lipase, which breaks down short-chain lipids into molecules consisting of two fatty acids. ... Both bile from the liver and lipase from the pancreas help digest lipids in the small intestine.

Microvilli are hairs that aid in absorption of nutrients. Nearly all of the nutrients you take in through your mouth are absorbed through the wall of the small intestine.

Digestion of fiber:

As above mentioned , this fibre is not absorbed by the body. These fibre products absorb water and passing out of the body as waste . These fibres help in digestion tract work smoother.

Chylomicron means ' milky - small ' molecules made of lipids and proteins. These are mainly found in blood and lymphatic vessels .

These transport the fat from the source of small intestine to sink of adipose tissue in liver.