Liver structure and function Flashcards
which lobe is bigger?
Right
what are the names given to the 2 minor lobes?
caudate
quadrate
what joins the common hepatic duct with the gallbladder?
cystic duct
what is the bare area of the liver?
small area on diaphragmatic surface surrounded by coronary ligament that is not covered by peritoneum
coronary ligament (not like ligaments we’ve come across before - this type is more an attachment) connects the liver to the under side of the diaphragm
What is the function of networks of septa that go deep into the body of the liver?
supports the liver
what do you find at each corner of the hexagonal shaped lobule?
portal triad ( contains hepatic portal vein, hepatic artery, hepatic duct)
which quadrant does the liver lie in
upper right quadrant of the abdomen
what enters/exits the liver via the Porta on its inferior surface (4)
blood vessels - hepatic portal vein and artery
lymphatic vessels
ducts - R/L hepatic duct
nerves (hepatic nerve plexus)
What do septa divide the liver into?
hexagonal lobules
What lies in the centre of each lobule?
central veins
which drain to hepatic veins that then drain to the inferior vena cava
what radiate out from central veins?
hepatic cords
what are hepatic cords composed of?
hepatocytes - functional cells of liver
Where are bile canaliculus located within the lobule? what is put into these channels
between cells within each cord
hepatocytes put their products (bile etc) into these channels
What is the space between hepatic cords called? and what is found within this space?
hepatic sinusoids - a discontinuous capillary network that allows for mixing of blood
blood channels
What do central veins do?
They receive the blood mixed in the liver sinusoids and return it to circulation via the hepatic veins.
What is the primary role of hepatocytes?
to make bile which they then secrete into canaliculi
Other functions of hepatocytes other than bile synthesis?
nutrient storage
(glycogen, fat, vits (B12,A,D,E,K), Cu, Fe)
nutrient interconversion - make and convert nutrients into any type of chemical really
detoxification of things like alcohol etc
Liver’s role with Glucose
The liver converts glucose to glycogen
It stores glycogen up to it’s maximum amount and after that a person has to tap into different energy stores
What role does the liver have within the alimentary system
production & secretion of bile
6 components of bile
Bile acids Lecithin cholesterol bile pigments - bilirubin toxic metals bicarbonate - neutralises acid chyme
What is common with all of these:-
Bile acids
Lecithin
cholesterol
they are synthesised in the liver
they solubilise fat - act as emulsifying agents
Bilirubin: yellow and brown pigment
if bilirubin is extracted from blood by hepatocytes and secreted into bile - yellow bile
bilirubin is modified by bacterial enzymes - brown faeces
How come urine is yellow?
reabsorbed bilirubin is excreted in urine
What colour is bilirubin pigment naturally
bright yellow
What do bile acids bind with to increase their solubility just before secretion?
glycine or taurine
this turns them into bile salts
what is a bile salt?
a conjugated bile acid
how are secreted bile salts recycled?
via the enterohepatic circulation
3 layers of gallbladder wall
mucosa - expansion
muscularis - contraction
serosa
Secretin is released in response to what? and what does it achieve
acid in the duodenum
neutralisation
how does secretin work?
it is released in response to acid in the duodenum
it decreases gastric acid secretion
decreases gastric emptying (slows time for food to move from stomach to small intestine)
increases duodenal HCO3 secretion
Increases pancreatic HCO3
increases bile duct HCO3 secretion
neutralised acid
Cholecystokinin (CCK) is released in response to what? and what does it achieve?
fat/amino acids in duodenum
digestion
how does CCK work?
decreases gastric emptying
increases pancreatic enzyme secretion - aid digestion
Gallbladder contraction
relaxation of sphincter of Oddi (surrounds end portion of the common bile duct and pancreatic duct. If relaxed - allows bile and pancreatic juice to flow into intestine)
