Hepatobiliary System Flashcards
(46 cards)
What are the upper and lower limits of the liver
Nipple and subcostal margin
What are the inflows and outflows of the liver
Inflow - Hepatic artery (25%), portal vein (75%)
Outflow - Bile, 3x hepatic veins
What is the purpose of blood delivered to liver by:
portal vein?
hepatic artery?
- From digestive system
- Supply oxygen and nutrients
Where is the 1st segment of the liver
Behind portal vein in front of vena cava
What is the micro-function of the liver
Acinus
Blood flow
Bile flow
What is the micro-morphology of the hepatic lobule
Hexagonal structural unit of liver tissue
Each corner consists of a portal triad - links with 3x adjacent lobules
Centre of liver lobule is a central vein - collects blood from hepatic sinusoids
Within lobule there are rows of hepatocytes - sinusoid facing side and bile canliculi facing side
What is the micro-morphology of portal triad
Branch of hepatic artery - O2 rich blood to support hepatocytes
Branch of portal vein - mixed venous blood from GIT (nutrients, abcteria nad toxins) and spleen (waste products), Bile duct - bile produced by liver drain into bile canliculi, coalesce with colangiocyte-lined bile ducts are lobule perimeter
What is the hepatic acinus
FUnctional unit of the liver
Consists of two adjacent 1/6th hepatic lobules
- Share 2 portal triads
- Extend into hepatic lobules as far as central vein
What is the three zone model of hepatic acinus
Blood into hepatic acinus via point A
Blood drains out of hepatic acinus via point B
Hepatocytes near outer hepatic lobule receive early exposure to blood contents - o2 but also toxins
What are the sinusoidal endothelial cells
No basement membrane
Fenestrated (discontinuous endothelium)
Allow lipid and large molecule movement to and from hepatocytes
What are kuppfer cells
Sinusoidal macrophage cells
Attatched to endothelial cells
Phgocytosis (eliminate substances arriving from portal circulation)
What are hepatic stellate cells
Exist in dormant state
Store VIt A in liver cytosolic droplets
Activated (fibroblasts) in response to liver damage
Proliferate, chemotactic and deposit collagen in ECM
Collagen cause damage cirrhosis
What are hepatocyte cells
Synthesis e.g. albymin, clotting factors and bile salts
Drug metabolism
Receive nutrients and building blocks from sinusoids
80% of liver mass
Cubical
What are cholangiocyte
Secrete HCO3 and H2O
What are the hepatocyte functions
Metabolic and catabolic functions: synthesis carbs, lipids and proteins
Secretory and excretory functions: syntehsis of proteins, bile and waste products
Detoxification and immunological functions: breakdown of ingested pathogens and processing of drugs
Where does anaerobic conversion of glucose happen
RBCs, renal medulla and skeletal muscle
Where does aerobic oxidation of glucose
CNS, heart, skeletal muscle, most organs
What is the cori cycle
Lactate to pyruvate using lactate dehydrogenase
Diagram of hepatocyte function - protein synthesis
Synthesis of non-essnetial amino acids
Different keto-acids being converted into multiple amino acids
alpha-keto glutarate - glutamate, proline, arginine
Pyruvate - alanine, valine, leucine
Oxaloacetate - aspartate, methionine, lysine
How do you resolve the issue that muscle can potentially utilise amino acids to produce glucose for energy
Convert pyruvate to glucose requires energy
Removing nitrogen as urea requires energy
Solution: transfer problem to the liver (glucose-alanine cycle)
What can alanine be converted to in the liver
Glutamate 0 can be converted to urea or combined with alpha ketogutarate to use in kreb cycle
Alpha ketoglutarate
Pyruvate
Diagram of triglyceride metabolism in liver
