Liver Flashcards
What are the three general functions of the liver?
1) Metabolism, including catabolism/anabolism of nutrients as well as their storage.
2) Detoxification
3) Bile production
What is the main source of detoxification in the liver?
Detoxification is primarily carried out by cytochrome P450 enzymes. These enzymes act on a wide range of substrates.
How are proteins, carbs, and fats processed or stored in the liver?
Proteins are procesed (i.e. turned into albumin), but not stored, in the liver.
Carbs or fats can be processed into and stored as glycogen or lipoproteins, while fat can also be stored as triglycerides.
Describe the blood supply to and from the liver.
The portal vein supplies nutrient rich blood from the intestinal tract, while the proper hepatic artery supplies oxygen rich blood from the heart. These blood supplies mix in the small blood vessels known as liver sinusoids.
The hepatic vein takes all of the blood out of the liver and back to the heart.
What is the portal triad?
The portal triad is primarily comprised of segments from the portal vein, the proper hepatic artery, and the hepatic duct.
Additionally, it includes lymph vessels and a branch from the vagus nerve.
Describe the structure of a hepatic lobule.
A hepatic lobule is a six sided ring packed with hepatocytes. On each point of the hexagon is a group of capillaries from the portal triad. In the center of the hexagon is the central vein, which gathers the nutrient and oxygen-poor blood and returns it to the hepatic vein.
What is bile comprised of?
Mainly water, with pigments and bile salts. Bile salts help to emulsify fat in the duodenum for digestion and absorption.
Describe the biliary tree
Bile is made in the (1) liver, where it is secreted into the (2) common hepatic ducts. It then travel though the (3) cystic duct and deposited in the (4) gallbladder for storage. Upon stimulation by cholecystokinin, or “CCK”, the gallbladder contracts and expels it back into the (5) cystic duct and through the (6) common bile duct into the duodenum.
Bile salts, as well as fats, are absorbed in the ileum and transported back to the liver through the portal vien.
