Liv4 Flashcards
surface anatomy
mainly upper R quadrant
protected by rib cage
gross anatomy
4 lobes R biggest L/ caudate lobe in middle quadrate lobe below it falciform ligament - attach to diaphragm common bile duct - lead to gall bladder
blood in liver
hepatic portal vein and artery to liver
hepatic vein - away
functional anatomy
cauinaud classification
8 functionally independent sections - own blood supply and venous drainage
central - HPV artery and bile duct
periphery - hepatic vein
blood supply
25% CO
dual - 20% hepatic artery, oxygenated and 80% HPV - deoxygenated from gut
HPV and artery mixed = overall poor oxygenation
hepatic vein drains into vena cava
purpose of hepatic artery
oxygen and nutrients
purpose of HPV
take breakdown products of gut
liver has a high metabolic rate
morphological anatomy
lobules
HPV and artery combine in sinusoid
lined by epithelia - substances can diffuce across into hepatocytes
sinusoid pass through lobule to central vein to vena cava
portal triad/tract - bile duct, HPV and artery
centrilobular hepatocyte - centre of lobe
periprotal hepatocyte
portal triad
around edge of lobule
acinus
functional
less well defined
unit of hepatocytes divided into zones dependant on proximity to arterial blood supply
zone 1-3
1 near portal triad - risk of viral infection
3 near central vein - risk of ischemia
hepatocytes
80% of the mass
large cell
pale and round nuclei
radiate from the central vein
which cells appear to be in sinusoids
kuppfer/stellate
flattened
dense nuclei
histology of non-parenchymal cells
endothelial cells - nuclei red and flat
Kupffer cells - cytoplasm blue, nuclei red
hepatocytes - nuclei red and round
stellate cells
vitamin A storage
activation = ECM formation - fibrinogenesis
respond to proinflammatory environment
important in cirrhosis - fibrotic lesion
sinusoidal endothelial cells
fenestrated - allow lipid and large molecule movement to and from hepatocytes
Kupffer cells
phagocytosis
including RBC breakdown
secretion of cytokines that promote stellate cell activation - fibrinogenesis
four functions of liver
control synth and met of protein
maintenance of blood sugar
lipid met
Metabolism and excretion of bilirubin and bile acids.
control synth and met of protein
albumin
transferrin - transport and carrier proteins
coagulation factors and complement
degradation of aa -> urea
Maintenance of blood sugar
release glucose
breakdown glycogen
synth glucose from aa or glycerol
Lipid metabolism.
manufacture most cholesterol -> make bile salts
synth lipoproteins and triglycerides
Metabolism and excretion of bilirubin and bile acid
bile acids are from cholesterol
metabolism of carbohydrates
store of glycogen only available for 24hrs
glucose enter muscle = TCA cycle/lactate production
lactate converted to pyruvate in liver via lactate dehydrogenase
pyruvate is converted to glycose by gluconeogenesis
requires 6ATP
synthesis of protein
aa from diet or muscle break down
enter liver
liver makes secreted proteins eg plasma proteins, clotting factors and lipoproteins
transamination
transfer essential to non-essential AA
keto acids are a go between
alanine transaminase
different transamination reactions
depends on the transaminase
a keto-glutarate –> glutamate, proline, arginine
pyrivate –> alanine, valine, leucine
oxaloacetate –> aspartate, methionine, lysine
why is deamination needed
muscle can use AA to produce glucose
but energy required to convert pyruvate to glucose and remove nitrogen
so job is given to liver
deamination
glucose-alanine cycle
pyruvate and glutamate form alanine in muscle alanine converted to glutamate and pyruvate in the liver
pyruvate converted back to glucose with addition of 6ATP - TCA
glutamate broken into urea by addition of 4ATP - utilised to make glucose
triglyceride metabolism
adipose tissue: triglyceride into FA
liver: FA vie B oxidation to acetyl CoA to TCA
OR liver generate ketones: 2x acetyl CoA -> acetoacetate - leave the liver as tissue energy source
lipoprotein synthesis
glucose enters converted to glycerol and pyruvate
pyruvate –> acetyl CoA
acetyl CoA –> FA and cholesterol
glycerol –> triacylglycerol
triacylglycerol+ apoproteins and phospholipids + cholesterol –> lipoproteins
action of lipoproteins
VLDL - transport FA to tissues
VLDL –> LDL
LDL converts chol to tissues
HDL - pick up excess chol, have few FA
storage
fat sol vit - A, E, D, K
A D E store sufficient for 6 month
store iron as ferratin - available for erythropoiesis
detoxification
phase 1 - P450 make more hydrophilic so easier to secrete in urine
phase 2 - attach water soluble side chain to make less reactive so less likely to leave blood until reaches kidney
