Liver

1) Liver Structure

A. Lobes of liver consist of hepatic lobules, the functional units of the gland

B. Bile canals carry bile from hepatic tubes to hepatic duct.

2) Liver functions

A. Metabolizes carbohydrates, lipids and proteins; stores some substances, filters blood, destroys toxins, and secretes bile.

B. Bile is the only liver secretions used directly for digestion.

3) Bile Composition

A. Contains bile salts, bile pigments, cholesterol, and electrolytes.

B. Only bile salts are used for digestion

4) Gallbladder

A. Stores bile between meals.

B. Sphincter muscle controls the release of bile from bile duct.

5) Regulation of bile release

A. Cholecystokinin from small intestine stimulates bile release.

B. Sphincter muscle at base of duct relaxes as a peristaltic wave in the duodenal wall approaches.

6) Function of Bile salts

Emulsify fats and aid in the absorption of fatty acids, cholesterol, and certain vitamins.