anatomy and physiology of the liver Flashcards
what is the largest visceral organ in the body
the liver
what is the colour of the liver dependendent on
fat content
what are the 2 surfaces of the liver
- diaphragmatic (superior, right, anterior, posterior)
- visceral (inferior) - touches other visceral organs
what abdominal quadrants does the lover occupy
- R hypochondrium
- epigastrium
- L hypocodrium
what capsule covers the liver
a fiborus capsule called the glisson capsule -> pain fibres are located here
what parts of the liver are not situated in the peritoneum (3)
- gallbladder fossa
- porta hepatis
- bare area
what divides the liver into left and right lobes
the falciform ligament
what are the 4 anatomical lobes of the liver
- right
- left
- quadrate
- caudate
what is the bare are of the liver
where the liver directly contacts the diaphragmatic surface and no peritoneum is present
what is the ligamentum teres in the liver
dense ligamentous band of fibrous tissue - It is a remnant of the fetal circulatory system, the umbilical veins
what is the lesser omentum
a double layer of peritoneum that runs from the inferior surface of the liver to the lesser curvature of the stomach and proximal duodenum -> it contaisn the hepatogastric ligament and hepatoduodenal ligament
(see notes for pic)
what is the porta hepatis
the entry/exit point for the most important structures of the liver -> portal vein, hepatic artery proper, hepatic nervous plexus, common hepatic duct, lymph vessels
what is Cantlie’s line
the ‘imaginary’ boarderline between both functional lobes of the liver
what is the boarder of the L and R functional liver lobes marked by
the IVC and gallbladder
where does the L functional liver lobe drain to and what supplies it
drains to L bile duct, supplied by portal vein
what is couinaud’s classification
divides the liver into eight functionally indepedent segments -> Each segment has its own vascular inflow, outflow and biliary drainage, In the centre of each segment there is a branch of the portal vein, hepatic artery and bile duct
what artery do bile duct hilum cancer often impact
the hepatic artery -> it sneaks behind the bile duct
what vein does all GI blood drain into
the portal vein
what veins join to form the main hepatic portal vein
the superior mesenteric vein and splenic vein (IMA joins the splenic earlier)
what are the components of the functional liver lobule (6)
- central tract
- hepatocytes
- bilary cannuiculi
- sinosoid cells
- arteries
- veins
what is the function of the sinosoid cells
takes blood from microscopic hepatic arteries/veins and drains it into the central vein -> all veins eventually join up to for the 3 main hepatic veins
what is the fucntion of the biliary canniculi
bile is formed here (in between the liver cells) -> then flows into he main bile duct
what zone hepatocytes are closes to the central vein
zone 3
|
/ / /\ \ \
/ 3 / 2 / 1 \ 2 \ 3 \
0 / / / | \ \ \ 0
(central vein) | (ctrl vein)
what are oval cells in the liver
stem cells that appear when the liver is damaged
what are hepatic stellate cells
a minor cell population in the liver but serve numerous critical functions in the normal liver and in response to injury -> thought to be responsible for collagen production in liver injury for which form the basis for fibrosis
what are kupffer cells in the liver
macrophages that line the lumen of the sinusoid
what heptaic membrane protein is responsible for importing bile acids into the hepatocyte
sodium taurocholate cotransporting polypeptide (NTCP)
what heptaic membrane protein is responsible for importing organic anions and bile acids into the hepatocyte
OATP
what are the hepatocyte exporter proteins (2)
- OST a/b
- MRP3/4
what hepatic protein is responsible for transporting bile acids from the hepatocytes into the bilary canniliculus
BSEP
why is the FIC1 protein important in bile formation
is ensures the asymmetry of phospholipids in the bilayer which is required for the other membrane proteins to work properly
why is the STEROLIN protein important in bile formation
transports cholesterol from the hepatocyte into the biliary canniliculus (excretery route)
why is the MRP2 protein important in bile formation
transports bilirubin into the biliary cannuliculus
why is the MDR3 protein important in bile formation
secretes phospholipids from the cytoplasm into the membrane
where is cholesterol converted into bile acids
in the hepatocytes
what enzyme is used to in the cholesterol -> bile acids classical conversion pathway
7-alpha-hydroxylase
what enzyme is used to in the cholesterol -> bile acids alternative conversion pathway
27-hydroxylase
what are the 2 primary bile acids produced from cholesterol
cholic acid and chenodeoxycholic acid
what are the bile acids conjugated to in order to increase their solubilty i.e. become bile salts (2)
the amino acids glycine or taurine
what are the 2 secondary bile acids and where do they arise
In the intestines, some of these primary bile acids get dehydroxylated, giving rise to secondary bile acids:
1. deoxycholic acid
2. lithocholic acid
what in the intestines caused the conversion of primary to secondary bile acids
the intestinal microbes
bile components (5)
- bile acids
- bile pigments (e.g. bilirubin)
- cholesterol
- phospholipids
- proteins
which bile acid makes up the majority of the BAs in bile
cholic acid
where can bile acids be resporbed
in the terminal ileum -> reabsorbed back into the blood stream to be taken back to the liver
what is the function of bile (3)
- emulsify fat
- cholesterol, triglyceride, fatty acid, fat-soluble vitamin absorption
- gut-liver axis -> critical in response to inflammation, immune response, epithelial cell proliferation etc.
what does bile acids binding to GPBAR-1 on kupffer cells do
regulation of liver immunity by modulating type I and II natural killer T cells in a interleukin-10 dependent manner
why does liver damage result in leg oedema
due to decrease albumin production leading to a change in intravascular oncotic pressure
what is the role of the liver in determining intravascular oncotic pressure
it makes albumin -> important in oncotic pressure
why must INR be measured in liver disease
the liver is essential in making clotting factors 2,7,9,10, as well as protein C, S and antithrombin => INR must be check to determine if these factors are being made
what reaction is urea a byproduct of
Arginine -> Ornithine
this takes place in the liver
why might hypoglycaemia be seen in acute liver failure
the liver is key in glycogen metabolism -> glucose cannot be adequately released from livers stores in acute liver failure
what is the cori cycle and what can it result in, in liver failure
glucose is metabolized to pyruvate and then to lactate in muscle, the lactate is released into the blood and carried to the liver, where it is reconverted to pyruvate and used for gluconeogenesis, and the resulting glucose is released and travels back to muscle
-> results in lactic acidosis in liver failure as the lactate isn’t being converted in the liver
what zone hepatocytes are particularly involved in drug metabolism
zone 3
