Liver Physiology Flashcards
functions of the liver
- metabolism: nutrients, drugs
- detoxification: bilirubin
- production: glucose, albumin
- storage: glycogen, vitamins, copper
lobes of the liver
- right lateral
- right medial
- quadrate
- left medial
- left lateral
- caudate
where is the gallbladder located
between right medial and quadrate lobes
normal appearance of the liver
red, smooth capsule
enhanced reticular pattern
distinct outline of lobules
indicates pathology (except pigs)
blood flow to the liver
dual blood supply:
- hepatic artery
- portal vein
hepatic artery
brings oxygenated blood directly from the heart
portal vein
brings deoxygenated blood from elsewhere in the body
supplies largest volume of blood to the liver
hepatic sinusoids
fenestrated sinuses between rows of hepatocytes that allows for nutrient exchange, absorption, and product secretion
allows for mixing of blood between hepatic artery and portal vein
central vein
located in the center of each liver lobule; receives nutrient rich blood after is passes through sinusoids
carries blood to hepatic vein
hepatic vein
takes blood away from liver to heart
hepatic acinus
functional unit of the liver that spans from hepatic train to central vein
divided into 3 zones
hepatic triad
hepatic artery + portal vein + bile duct
zone 1
periportal zone; located closest to hepatic triad
receives most oxygen and nutrient rich blood
zone 3
centrilobular zone; located closest to central vein
receives deoxygenated blood
site of drug metabolism
rate of blood flow through the liver
must remain constant
main regulator of blood flow
hepatic artery
uses adenosine washout
effect of adenosine on hepatic blood flow
inhibits vasoconstrictors to cause hepatic artery to dilate
does NOT affect portal vein
adenosine gets washed away by venous and arterial flow
adenosine washout
maintains constant rate of blood flow
as portal vein flow increases –> adenosine gets washed away quickly –> hepatic artery constricts –> hepatic artery flow decreases
as portal vein flow decreases –> adenosine remains longer –> hepatic artery dilates –> hepatic artery flow increases
affect of liver disease on blood flow
liver disease causes ascites :
1. hypoalbuminemia –> decreases oncotic pressure –> water flows out of vessels –> ascites
2. decreased hepatic blood flow –> increased hydrostatic pressure In portal vein – leakage –> ascites
hepatocytes
functional unit of the liver; maintains plasma oncotic pressure by producing albumin, stores glycogen, vitamins, copper, and iron
has abundant mitochondria
hepatocyte polarity
basal side: (top and bottom) faces sinusoids
apical side: (between hepatocytes) faces bile canaliculi
kupffer cells
macrophages in the liver
enzymes that indicate cell injury
ALT, AST, GGT
(leakage enzymes)
acute phase proteins
albumin, bilirubin, glucose, cholesterol, blood urea nitrogen
assess liver function
