The Liver And Biliary System Biology Essay

According to the (University of Rochester Medical Center Rochester, The Biliary System: Anatomy and Functions 2021), The biliary system comprises organs and ducts that aid in the transport and creation of bile. The organs and ducts include the bile ducts, gallbladder, and related structures.

Bile is a  greenish-yellow fluid that is secreted by the liver cells. Bile consists of 97 % water, the rest consists of electrolytes, bile acids, cholesterol, phospholipids, and conjugated bilirubin. It is slightly alkaline with a pH of about 7 to 8.

Red blood cells unceasingly experience a hemolysis process by which red blood is broken down every 120 days,  as this is their basic life span. As the red blood cells disintegrate, the hemoglobin is then broken into globin, with the protein part called iron is sent to the bone marrow and the production of heme. The heme breaks apart into biliverdin, which is a green pigment called bilirubin. The bilirubin is then transported to the liver where it reacts with a solubilizing sugar called glucuronic acid. Bilirubin is then conjugated and excreted into the bile. 

The two main functions of bile are to emulsify fat in the ileum of the small intestine and to carry away waste.

The bile leaves the liver through the Left Hepatic Duct and Right Hepatic Ducts. Both ducts meet at the Common Hepatic Duct. The bile then goes through the Cystic Duct then into the Gallbladder for storage, The gallbladder is a pear-shaped organ that is situated below the liver and its function is to store bile.

When food is eaten, the  Cholecystokinin (CCK)  hormone is secreted, which gives a signal to the gallbladder to squeeze the bile back into the Cystic Duct. The bile then travels through the Cystic Duct to reach the Common Bile Duct where it travels into the lower portion of the Common bile duct that joins the pancreatic duct before flowing into the duodenum. Pancreatic juices (comprising digestive enzymes) enter the biliary system at this point before passing the sphincter of Oddi, which regulates the flow of the bile, into the first part of the small intestine called the Duodenum.

Fat is emulsified in the Duodenum, Absorption of fats and bile salts takes place in the Ilium where  95%  of the Bile is taken back to the liver by the portal vein, The next 5% is excreted in feces.

References

Bilirubin. http://chemistry.elmhurst.edu/vchembook/634bilirubin.html.

Encyclopædia Britannica, inc. Bile. Encyclopædia Britannica. https://www.britannica.com/science/bile. 

The Biliary System: Anatomy and Functions. Biliary System: Anatomy and Functions - Health Encyclopedia - University of Rochester Medical Center. https://www.urmc.rochester.edu/encyclopedia/