Physiology of Liver – outline notes

The liver is an amazing organ. A single hepatocyte (liver cell) can conduct over 1000 metabolic reactions. Here is an overview of some of the highlights of the liver.

1. Metabolic Regulation
-blood leaving digestive tract enters hepatic portal system and flows to the
liver
-regulates composition of circulating blood


Examples
–Carbohydrate metabolism
-stabilizes blood glc around 90 mg / dl
-glycogenolysis – glycogen to glc
-gluconeogenesis – synthesis of glc from other sources (a.a.’s)
-glycogenesis
-insulin and glucagon
–Lipid metabolism
-lipoproteins
-Amino acid metabolism – converts a.a’s to lipid or glc
-Removal of waste products
-deamination – remove amino groups from a.a.’s
-ammonia is produced and liver converts to urea
-other wastes
-toxins, drugs (also drug inactivation)
-Fat-soluble Vitamin and Mineral storage (Fe)

2. Hematological regulation
-receives about 25% of Cardiac Output
-Kupffer cells – remove old RBC’s, debris, pathogens
-antigen-presenting cells that can stimulate immune response
-Plasma protein synthesis
-albumin, clotting proteins, complement, transport proteins
-Remove circulating hormones
-NE, Epi, insulin, steroids, corticosteroids
-removal of antibodies

3. Synthesis and secretion of Bile
-bile is composed of water, ions, bilirubin, cholesterol and lipids
-enterohepatic circulation of bile
-circulation of bile from liver to small intestine and back to liver