What is Bile? : importance and functions

What is Bile?

Bile is a yellow-green or green-blue colored alkaline (pH – 7.6 to 8.6) liquid. Humans secrete about 800 to 1000 mL of bile daily. Bile released from the gallbladder into the duodenum contains about 92% water, 6% bile salts, 0.3% bile pigments – bilirubin and bile acids, 0.3-0.9% cholesterol, 0.3% lecithin and 0.3 to 1.2 % fatty acids. Bile salts include inorganic salts such as sodium chloride and sodium bicarbonate and organic salts such as sodium glycocholate and sodium taurocholate.

Functions of Bile: Bile does not contain any digestive enzymes, but it plays an important role in the digestion and absorption of lipids and has many other functions as well. All its functions are as follows- 

1. It increases intestinal peristalsis, mainly the mixing motions so that the digestive juices are well mixed in the chyme.
2. Its inorganic salts neutralize the effect of HCI and make the chyme alkaline so that it can react with pancreatic and intestinal juices.
3. Bile salts protect the chyme from putrefaction by destroying the harmful bacteria of the chyme.
4. Its organic salts reduce the surface tension of the fats of the chyme and break them into small globules so that the lipase of the pancreatic juice can react to them to the maximum. These tiny droplets of fat form an emulsion with bile water similar to the oil and water we see on our shoulders in winters. Hence, it is called emulsification of fat.
5. Bile salts activate fat-digesting enzymes.
6. Together with bile acids, lecithin, and cholesterol, bile salts form microscopic droplets called micelles that aid in the absorption of lipid digestion products. Bile salts are necessary for the absorption of fat-soluble vitamins (A, D, E, and K).
7. Bile acts as an excretory medium for the elimination of toxins, metals, and unnecessary cholesterol. Bile pigment (bilirubin) is the only excretory substance. It is released in the blood after the breakdown of hemoglobin in the bone marrow, spleen, lymph nodes, liver, etc. Liver cells excrete it from the blood with bile in the same way that kidney cells excrete urea. Due to this, the bile is yellow or greenish.

Read more: Blood

Jaundice disease: In reticuloendothelial tissues (spleen ie spleen, bone marrow, lymph nodes, etc.), the rate of red blood cell fragmentation of blood is greatly increased, a large number of liver cells is damaged, Or when the passage of bile from the gallbladder to the bile duct is blocked, the liver cells are unable to take up bilirubin from the blood. Therefore, yellow bilirubin remains in the blood and spreads throughout the body. This is called jaundice. In this, the skin and eyes become yellow, the urine becomes yellow-greenish and the stool becomes brown. In the absence of proper treatment, the patient dies.