Question

Describe physiology of digestion in detail.

Answer 1

1. Digestion begins in the oral cavity by the action of saliva which contains salivary amylase that breaks down starch into disaccharide.
2. Food is reached to stomach and HCl is mixed which activates pepsinogen into pepsin that breaks down proteins into dipeptides and converts into chyme with pH 2-3.
3. Chyme is reached to the duodenum of the small intestine and pancreatic enzyme acts on it. Enterokinase activates trypsinogen, chymotrypsinogen, and procarboxypeptidase into trypsin, chymotrypsin and carboxypeptidase and digest rest of the protein to dipeptidase.
4. Starch is breakdown into disaccharides by the action of pancreatic amylase.
5. Fat is emulsified by bile juice and further convert into the micelle.
6. The succus entericus acts on rest of dipeptides, disaccharides and on micelles to form glucose, galactose, fructose, amino acid, and fatty acids.
7. Nucleic acids are converted into nucleotides and then into nucleosides by nucleases.
8. These are absorbed by intestinal wall and release to the bloodstream.