Question

Bile contains no digestive enzymes. Yet it is important for digestion. How?

Answer 1

Bile juice is secreted in the small intestine for the digestion of fat. It is formed in the liver. It flows continuously and the remaining gets stored in the gallbladder.

Complete answer: Bile is a fluid which is dark green to yellowish brown in colour. It is secreted by the liver in the majority of the vertebrates. This juice helps in the digestion of the lipids.
In the case of humans the bile is secreted throughout the day. The remaining bile is stored in gallbladder. On food consumption, this bile gets secreted into a part of the small intestine i.e duodenum for the digestion.
The composition of bile juice is water i.e 97-98%, bile salts i.e 0.7%, bilirubin i.e, 0.2%, fat i.e 0.51% and inorganic salts.
Bile has two components— bilirubin and biliverdin.
Bilirubin is yellow orange in color and biliverdin is green in color.
These are the reasons for the faecal matter to have a brown tone.
Bile helps in the digestion of lipid content. It also increases the absorption of fat and fat soluble substances such as vitamin A, D, E and K. It does not contain any digestive enzymes.
Bile juice helps in breaking down large fat molecules into smaller ones which makes it further easy for the pancreatic enzymes to carry out their function. This process in the digestion is called emulsification.

Note: Bile serves as a route for excretion of bilirubin. Bile can be alkaline at times. When it is in alkaline state it neutralises the stomach acid before it flows into the duodenum. It can also act as a bactericidal fluid.