Table of Contents
What is Bile?
Bile, also known as gall, is an aqueous solution that is yellowish-green-brown in colour. It is formed in the liver of the majority of vertebrates and is a vital component for the survival of organisms. It is secreted by the hepatocytes continuously and eventually stored in the gallbladder. It is then transported to the intestinal lumen whenever required. Bile plays an important role in the digestion of lipids in the small intestine.
Composition
The bile is composed of ~95% water, which has dissolved solid constituents such as bile salts (0.7%), bilirubin (0.2%), fats (0.51%) such as cholesterol, fatty acids and lecithin, inorganic salts, vitamins and environmental toxins. The green and yellow colour of the bile is achieved from the two pigments biliverdin (oxidised form of bilirubin) and bilirubin, respectively.
Functions of Bile
- The bile forms an important excretory router for bilirubin (a byproduct of RBCs) and other harmful lipophilic substances.
- Bile salts, one of the important components of bile, help in emulsifying fats and also increase their intestinal absorption.
- Cholesterol is also eliminated via bile.
- Cytokines and IgA are excreted into the bile which stimulates the innate immune system and saves the organism from enteric infections.
- It is an important component of enterohepatic and cholehepatic circulation.
- Many hormones and pheromones are excreted in the bile as well that help in the development of the intestine.
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Also Read:
- The Role of Digestive Enzymes and Gut Hormones in Digestion
- Liver – Anatomy, Functions, and Liver Diseases
