Liver Structure and Function Flashcards
What is the anatomy of the liver?
2 major lobes - right and left
2 minor lobes - caudate and quadrate
What is the porta?
The region on the inferior surface of liver where the hepatic artery, portal vein and duct enters/exits
How many hepatic ducts are there?
Right and left that both feed into the common hepatic duct
What nerve supply does the liver have?
Hepatic nerve plexus
Where does the common hepatic duct go?
Common hepatic duct joined by cystic duct from the gallbladder
Then feeds into common bile duct + pancreatic duct which goes into the sphincter of oddi to the duodenum
What is the liver covered by?
A CT capsule Visceral peritoneum (except for bare area)
What is the bare area?
Small area on the diaphragmatic surface which is surrounded by coronary ligament
What is the structure like at the porta?
A CT capsule
A branching network called septa which goes into body of liver to support it
What does the septa do to the liver?
Divides it into hexagonal lobules
What is the portal triad?
hepatic artery, vein and duct - these 3 are located at each corner of the hexagonal lobules
Some nerves and lymphatics also there
What is in the middle of the hexagonal lobules?
Central veins that drain into the hepatic veins
What radiates out from the central veins like spokes on a wheel?
Hepatic cords - made from hepatocytes, the functional cells of the liver
What is the bile canaliculus ?
A cleft like lumen that lies between the cells of each hepatic cord
What are the spaces between the hepatic cords called?
Hepatic sinusoids
What is the alimentary role of the liver?
Production and secretion of bile
What is bile made from?
Cholesterol
What is the difference between a bile acid and a bile salt?
Before secretion - bile acids are conjugated with glycine or taurine making it a bile salt which increases solubility
Where do bile pigments come from?
Bilirubin - extracted from blood by hepatocytes and excreted into bile making yellow bile
Why is bilirubin brown in faeces?
Modified by bacterial enzymes turning pigments brown
Why is urine yellow?
Reabsorbed bilirubin excreted in urine
What is bicarbonate secreted by?
Duct cells
Shape and location of gallbladder?
Sac like
Inferior surface of liver
Layers of the gallbladder?
Mucosa - folded rugae
Muscularis - smooth muscle
Serosa - CT
How does the gallbladder transport bile?
Feeds into cystic duct which feeds into the common bile duct
What controls bile secretion?
Presence of fat in duodenum causes release of CCK
CCK causes sphincter of oddi to relex and the gallbladder to contract
Summarize what secretin does.
Acid in the duodenum releases secretin which =
- Reduced HCL secretion
- Reduced gastric emptying
- Increased duodenal, bile duct and pancreatic bicarb secretion
Summarise what cholecystokinin does.
Fat/acid in duodenum = release of cholecystokinin =
- reduced gastric emptying
- increased pancreatic enzyme secretion
- increased bile secretion
- relaxation of sphincter of oddi
