Liver Biochemistry Flashcards
What is the largest solid organ in the body?
liver
3% body weight
How many lobes are there?
2 main lobes which are subdivided into multiple lobes and sinusoids
What is the liver covered by?
capsule of CT
What is the blood supply of the liver
75% portal vein
25% hepatic artery
What is the biliary components made of?
bile ducts and gall bladder
Describe hepatic circulation
- oxygen rich blood flows into the liver through the hepatic artery (25%)
- nutrient rich blood coming through the bowel flows into the liver through the portal vein (75%)
- bile flows out of the liver through the bile duct
- blood flows out of the liver through 3 hepatic veins into a big vein called the IVC
What can be seen in a cross section of a liver lobe?
- hepatic sinusoid
- hepatocyte
- central vein
- interlobar bile duct
- interlobar vein
- interlobar artery
What types of cells are in the liver?
- hepatocytes
- endothelial cells
- Kupffer cells
- hepatic stellate cells
- pit cells (lymphocytes)
- cholangiocytes
What are hepatocytes?
80% of liver cells, carry out most of the metabolic functions of the liver, capable of regeneration
What do endothelial cells do in the liver?
allow exchange of material from liver to blood and vice versa via pores and fenstrations in plasma membrane
What are Kupffer cells?
- present in the lining of the sinusoids
- are macrophages that protect the liver from gut derived microbes, remove damaged/dead RBCs, orchestrate immune response, secrete cytokines.
- have well developed endocytic and phagocytic functions, lots of lysosomes present in these cells
What are hepatic stellate cells?
serve as storage site for vitamin A and other lipids
What are pit cells?
lymphocytes
-NK cells, protect liver against viruses and tumor cells
What are cholangiocytes?
line bile ducts
control bile flow rate and bile pH
What are the functions of the liver?
- primary receiving, distribution, and recycling center
- carbohydrate metabolism
- liver metabolism
- neucleotide biosynthesis
- amino acid metabolism, ammonia, and urea cycle
- protein and amino acid metabolism
- synthesis of blood proteins
- bilirubin metabolism
- waste management
How does the liver participate in carbohydrate metabolism?
- glycolysis
- glycogenesis and glycogenolysis
- gluconeogenesis
- glucostasis (maintains glucose levels under fed, fasting, and starvation state)
How does the liver participate in lipid metabolism?
- biosynthesis of triacylglycerols (TAGs), phospholipids, steroids (cholesterol, bile acids, and bile salts), lipoproteins (VLDL, LDL, HDL)
- degredation of TAG and plasma lipoproteins
- regulation of free fatty acid (FFA) metabolism
- breakdown of FFA via beta oxydation to release energy
What are the blood proteins the liver synthesizes?
- albumin
- IgGs
- apoproteins
- fibrinogen
- prothrombin
- blood coagulation factors V, VII, IX, and X
- CRP
- alpha 1 antitrypsin
- alpha 1 antichymotrypsin (acute phase proteins)
How is the liver involved in waste management?
-inactivation, detoxification, and biotransformation of metabolites and xenobiotics
What is a majory role fo the liver?
monitoring, synthesizing, recycling, distributing, and modifying metabolites
What does the liver do to useful ingested material and harmful products?
useful: retrieved by the liver and converted into a useful form
harmful: converted into a safe product and excreted
Describe the unique circulation of the liver
- liver receives blood from enteric circulation via portal vein and from periphery via hepatic artery
- low portal blood pressure
Does the liver have basement membrane?
NO
Does the liver have tight junctions between hepatocytes and endothelial cells?
NO