Cholesterol significance in animals
Cholesterol belong to the group of steroid present in animal fat. About 10% of the bile is the cholesterol, secreted by hepatic cells. There are two principle sources of cholesterol in the bile-
- Synthesized by the hepatic cells
- By absorption from the intestine through portal circulation to the liver
Gall stones and their formation
- Two kinds of gall stones are formed
- Cholesterol and bile pigments
- Cholesterol, bile pigments and CaCO3 with other fatty substances
The cholesterol is insoluble in the water. Bile salts, fatty acids and lecithine present in the bile provide hydrophobic property to cholesterol and keep it as solution in bile . When the bile becomes concentrated, these hydrophobic substances also get concentrated.
Under abnormal conditions, cholesterol may be precipitated which results in the formation of gall stones in the bladder.
- The following are the conditions that cause cholesterol precipitation-
- Excessive absorption of water from the bile
- Excessive absorption of hydrophobic substances
- Excess secretion of cholesterol in bile
- Inflammation of the gall bladder epithelium.
Inflammation of gall bladder epithelium alters the absorption of water, bile salts or other hydrophobic substances through gall bladder mucosa.
Excessive absorption of water, bile salts or other hydrophobic substances, leads to precipitation of cholesterol .
Many small cholesterol crystals act as a nidi or nucleus which favours further deposition of cholesterol crystals leads to occurrence of multiple gall stones.