Liver structure and function Flashcards
What is secretin?
A hormone released into the bloodstream by the duodenum (especially in response to acidity) to stimulate secretion by the liver and pancreas
What is the largest organ in the body?
Liver
- Weighs 1.4kg
What are the 2 major and minor lobes of the liver?
2 major lobes: Right > Left
2 minor lobes: Caudate, Quadrate
What is the porta hepatis?
The fissure running transversely on the underside of the liver where most of the vessels enter or leave
What structures enter or leave the liver at the porta hepatis?
The portal vein, the hepatic artery, and the common hepatic duct
What is the common hepatic duct joined by?
Common hepatic duct joined by cystic duct from gallbladder > common bile duct + pancreatic duct > major duodenal papilla (Sphincter of Oddi)
Whats the ligament that passes down between the right and left lobe of the liver?
Falsiform ligament
What ligament from the liver attaches to the underside of the diaphragm?
Coronary ligament
What is the liver covered by?
Liver covered by connective tissue capsule and visceral peritoneum except for bare area (small area on diaphragmatic surface surrounded by coronary ligament)
What does the septa divide into?
Septa divides into hexagonal lobules
What is the portal triad composed of?
Hepatic portal vein
Hepatic artery
Hepatic duct
Where is the portal triad located?
At each corner of hexagonal lobule (also nerves and lymph vessels)
Where do the central veins go?
Central veins at the centre of the hexagon form hepatic veins then these drain into the inferior vena cava
Where do hepatic cords radiate to?
They radiate out from central veins (like spokes of wheels)
- Hepatic cords are composed of hepatocytes
What is the bile canaliculus?
Bile canaliculus is a thin tube that collects bile secreted by hepatocytes.
- The bile canaliculi empty into a series of progressively larger bile ductules and ducts, which eventually become common hepatic duct.
What are the spaces between hepatic cords called?
Hepatic sinusoids (blood channels)
What are sinusoids?
They are low pressure vascular channels that receive blood from terminal branches of the hepatic artery and portal vein and deliver it to central veins
What is the movement of blood and bile from the liver lobule?
Blood travels from the portal triad inside to the central vein outside
Bile travels from the central vein inside to the bile canaliculus outside
What is the sequence of the hepatic portal vein artery drainage?
Hepatic artery/ portal vein > Hepatic sinusoids > central veins > hepatic veins > inferior vena cava
What are the functions of hepatocytes?
Bile synthesis
Nutrient storage: glycogen fat, vitamins (B12, A, D, E, K), Cu, Fe), nutrient interconversion, detoxification
What is the main alimentary role of liver?
Production & secretion of bile
What are the six components of bile?
Bile acids
Lecithin
Cholesterol
Bile pigments - bilirubin (from haemoglobulin)
Toxic metals - detoxified in liver
Bicarbonate - neutralisation of acid chyme
Which components of bile are synthesised in liver and soluble in fat?
Bile acids
Lecithin
Cholesterol
What is HCO3 secreted by?
Duct cells
