Liver is an important and essential metabolic organ of the body. The liver can secrete the bile. Although bile is not a digestive juice in its, strict sense, it is helpful, rather essential for digestion and absorption for fats, hence it is considered along with digestive juices.

Bile Juice:

Bile juice is clear viscid, yellow or orange colored, bitter fluid. Although it does not contain digestive enzymes it is important in processes of digestion and is considered essential for life. Its composition includes:

Inorganic and Organic Constituents:

Inorganic Constituents:

Cl, CO₂, PO₄ of Na, K and Ca, and NaHCO₂.

Organic Constituents:

1. Mucin

Bilirubin

1. Bile pigments

Biliverdin

• Bile Salts: Sod, taurocholate and sod, glycholate.

1. Cholesterol and lecithin
2. Fats and fatty acids.

Functions of Bile:

• Excretion of bile pigments and other waste products.
• Bile salts emulsify fats and also render them water-soluble.
• Bile salts activate lipases.
• Bile salts aid in fat absorption by forming water soluble complexes with fat and carrying them across the absorbing epithelium.
• Similarly, the absorptions of fat soluble vitamins i.e., A, D,E, and K are also carried out.
• Bile helps to keep cholesterol in solution.
• It also excretes cholesterol and lecithin.
• Bile salts stimulate peristalsis and in a way act as laxatives.
• Bile salts act as cholagogues.
• Mucin of bile has a lubricating action.
• Bile helps to neutralize the acid reaction of gastric juice.
• The acidity of gastric juice while in stomach is neutralized to certain extend by regurgitation of bile from duodenum into stomach.