Jejunum and Ileum
- The ileocecal sphincter at the junction of the ileum and the large intestine, functions to limit the reflux of colonic contents back into the ileum.
- The jejunum and ileum secretes a juice called succus entericus which contains the following:
Five types of enzymes degrade disaccharides into monosaccharides:
1. Sucrase, which breaks down sucrose into glucose and fructose
2. Maltase, which breaks down maltose into glucose.
3. Isomaltase, which breaks down maltose and isomaltose
4. Lactase, which breaks down lactose into glucose and galactose
5. Intestinal lipase, which breaks down fatty acids
The small intestine receives lipase, trypsin and amylase from the pancreas. They are transported from the pancreas to the duodenum through the pancreatic duct. - Protein, fats and starch are broken down into smaller molecules, (although they are not fully broken down yet.)
- This causes the enzymes of the small intestine to act upon them. These enzymes include peptidase, which breaks down peptides into amino acids and the enzyme maltase acts upon maltose which produces glucose.
- These molecules are absorbed by the villi in the small intestine and according to the molecule they are either absorbed by the lacteal or blood capillaries