As the contents of the stomach become thoroughly liquefied, they pass into the duodenum(Small intestine). Duodenum is the first segment (about 10 inches long) of the small intestine.
Two ducts enter the duodenum:
- one draining the gall bladder and hence the liver
- the other draining the exocrine portion of the pancreas.
Bile
- pH 7.6
- bile acid: large globules of fat (liquid at body temperature) are emulsified into tiny droplets (about 1 µm in diameter) that can be more easily digested and absorbed.
- Bile contains the products of the breakdown of hemoglobin removed by the liver from old red blood cells. The brownish/greenish color of the bile pigments imparts the characteristic brown color of the faeces.
Pancreatic juice
- The pancreas consists of clusters if endocrine cells and exocrine cells whose secretions drain into the duodenum.
- Contains:
- sodium bicarbonate (NaHCO3): This neutralizes the acidity of the fluid arriving from the stomach raising its pH to about 8.
- pancreatic amylase: This enzyme hydrolyzes starch into a mixture of maltose and glucose.
- pancreatic lipase: The enzyme hydrolyzes ingested fats into a mixture of fatty acids and monoglycerols. Its action is enhanced by the detergent effect of bile.
- trypsin