hepatic system

9 flashcards · Other · by Louise Cox

1. the liver

   Is the largest internal organ centre for metabolic regulation 1/3 of its blood supply is from the hepatic artery 2/3 us venous blood from the hepatic portal vein it has a dual blood supply which is unique blood leaves the liver by the hepatic vein it is composed of 4 lobes - right , left , caudate and quadrate performs metabolic and synthetic functions

2. hepatic portal system

   carries blood rich in nutrients absorbed by food begins in the capillaries in the GIT ends in the liver sinusoid largest vessel is the hepatic portal vein delivers venous blood to the liver by inferior mesenteric vein splenic vein superior mesenteric vein HPV is a fusion of these 3

3. Hepatic portal vein

   HPV carries blood rich in nutrients absorbed from food filters toxins absorbed along with food First pass metabolism Conc of drug greatly reduced before it enters the systemic circulation reduced bioavailability

4. histology of the liver

   each lobe is divided into 100,000 lobules roughly 1mm in diameter lobule is the basic functional unit of the liver lobules are composed of hepatocytes hepatocytes form series of irregular plates sinusoids between plates empty into the central vein lining of sinusoids contain Kupffer cells > part of the reticuloendothelial system > cells engulf pathogens , cell debris and damaged cells blood enters the sinusoids from the HPV and hepatic artery portal triad at the corners of each lobule also cont…

5. physiology of the liver

   3 general functions : metabolic regulation haematological regulation bile production

6. physiology of the liver : metabolic regulation

   regulates composition of circulating blood carbohydrate metabolism >stabilises blood glucose levels > low blood glucose , hepatocytes break down glycogen reserves releasing glucose > synthesise glucose from amino acids - gluconeogenesis >high blood glucose , remove glucose from the blood - story as glycogen or make into lipids lipid metabolism amino acid metabolism waste product removal > liver deaminates amino acids during metabolism >ammonia is produced , converted to urea which is excreted b…

7. physiology of the liver :haematological regulation

   phagocytosis and immune response synthesis of plasma proteins removal of circulating hormones removal of antibodies

8. physiology of the liver : bile production

   synthesis and secretion of bile secreted into the duodenum bile is composed of water , bilirubin ,ions , cholesterol and bile salts dietary lipids are not water soluble in the stomach large lipid droplets are produced pancreatic lipase acts on surface lipids bile emulsifies lipids

9. the gall bladder

   hollow pear shaped organ which stores and concentrates bile inferior to the liver bile released into the duodenum under the control of the hormone cholecystokinin when chyme enters duodenum CCK is released , hepatopancreatic sphincter relaxes , gall bladder contracts bile excreted conc. CCK released is proportional to lipid conc in chyme