Chapter 15 - Liver and Gallbladder
The liver is an accessory digestive gland that performs hundreds of distinct functions that impact all body systems. The major functions of the liver can be broadly classified into four groups:
- Carbohydrate, protein, and lipid metabolism
- Storage of glycogen, vitamins, and iron
- Detoxification of harmful metabolites and drugs
- Production and secretion of bile
The liver is the largest internal organ of the body. The principal cell of the liver is the hepatocyte. These epithelial cells are arranged in branching plates separated by capillary sinusoids. The liver filters blood that comes from the digestive tract before passing it to the rest of the body.
Hepatocytes produce bile that is released into small, bile canaliculi formed by the plasma membranes of adjacent hepatocytes.
Kupffer cells are macrophages that reside in capillary sinusoids of the liver.
The blood supply to hepatocytes can be seen after perfusion with India ink.
Liver - Glycogen
Glycogen is a branched polysaccharide of glucose that represents the main storage of glucose in the body. The two major sites of glycogen storage are the liver and skeletal muscle. Glycogen synthesis and degradation in the liver are regulated to maintain blood glucose levels.
Liver - Lipids
Fatty liver diseases, or hepatic lipidosis, are the most common forms of liver disease.
In addition to its other functions, the liver is a site of blood formation (hematopoiesis) in the fetus.
The main functions of the gallbladder is storage, concentration, and release of bile. When released into the small intestine, bile helps break down and the absorption of fats, cholesterol, and some vitamins.