Wednesday, May 2, 2012

Digestive Tract #2

This is a continuation of Digestive Tract #1.

Small Intestines:
After turning into chyme, the food enters the small intestines, which are comprised of three parts:
  • Duodenum: receives secretions from the gall bladder and the pancreas (pancreatic juice). It is where the majority of chemical digestion takes place
  • Jejunum: absorption of carbohydrates and proteins takes place
  • Ileum: absorption takes place, especially vitamin B-12 and bile salts

Large Intestines:
The large intestines absorb water, and they also contain bacteria that produce vitamin K and vitamin B-12. In addition, they pass waste material to the anus.

The anus expels the wastes.

The pancreas secretes bicarbonate ions, which neutralize the stomach acid and inactivates pepsin. The pancreas also secretes pancreatic juice, which is comprised of pancreatic amylase (breaks down starch), lipase and trypsin.

Gall Bladder:
The gall bladder stores bile, which emulsifies fat and allows a greater surface area for fat to be broken down .

The liver produces bile and cholesterol. It also converts excess glucose to glycogen, detoxifies poisons, and stores fat-soluble vitamins.