What are some results from breakdown of bolus in the stomach?
1. Carbohydrates:
- Salivary amylase continues to break down carbohydrates in the stomach.
- Gastric acid denatures salivary amylase and stops its action when the pH drops below 4.
2. Proteins:
- Pepsin is secreted in an inactive form called pepsinogen. Hydrochloric acid (HCl) activates pepsinogen into pepsin.
- Pepsin cleaves peptide bonds on the carboxyl side of aromatic amino acids (phenylalanine, tyrosine, and tryptophan).
3. Fats:
- Stomach has no enzymes to digest fats. However, fats may undergo some physical changes:
- Some triglycerides may be hydrolyzed to fatty acids and glycerol by gastric lipase.
- Emulsification of fats into smaller droplets by mechanical agitation of stomach contractions.
4. Nucleic Acids:
- Nucleases may hydrolyze some dietary nucleic acids to form nucleotides in the stomach.