Structure and Function of the Liver Flashcards
Names the major and minor lobes of the liver
Right & Left (major)
Caudate & Quadrate (minor)
Location of the Liver
Right hypogastrium and epigastric areas, extending into the left hypogastrium
Is the liver completely peritonised ?
The posterior aspect of the diaphragmatic surface is not in contact with the peritoneum and makes direct contact with the diaphragm. This is known as the ‘bare area’ of the liver.
The liver is also covered by a connective tissue capsule
What is the falciform ligament?
Divides the left and right lobe of the liver and attaches the anterior surface to the anterior abdominal wall.
What is the coronary ligament
Attaches the superioir surface of the liver to the inferioir surface of the diaphragm
How does the lesser omentum interact with the liver?
The lesser omentum connects the liver to the lesser curvature of the stomach and the first part of the duodenum.
How does the liver interact with the vena cava?
The posterior surface of the liver is secured to the inferior vena cava by hepatic veins and fibrous tissue.
Describe the Caudate lobe
Located on the upper aspect of the surface
Describe the Quadrate
Located on the lower aspect of the visceral surface
Porta Hepatis
Transverse fissure separating the caudate and quadrate lobe on the inferior surface
It transmits the left&right hepatic ducts, hepatic arteries and portal vein. (anterior–> posterior). Components of portal triad
Arrangement of the Hepatocytes
Hepatocytes are arranged into structural hexagonal units called lobules,
At each corner exists a portal triad
At centre of the hexagonal unit, the central vein drain blood to the hepatic veins => IVC
Drainage of the Bile
Bile is drained through the bile canaculi into large collecting ducts of the intrahepatic portal triad.
These merge to porn the left&right hepatic ducts which drain the left and right lobes of the liver and latterly the common hepatic duct.
On it’s right side it forms a union with the cystic duct from the gallbladder to form the bile duct
The bile duct then forms the hepaticpancreatic ampulla with the pancreatic duct.
What is the Sphincter of Oddi and it’s action and it’s other name.
Major Duodenal Papilla
The smooth muscle that surround the end portion of the common bile and pancreatic duct. It relaxaes to allow bile and pancreatic juice to flow into the intestine.
What are Septa?
The septa is connective tissue that divide’s the liver into their hexagonal lobules
Components of the portal triad
Portal Vein & Artery and hepatic duct.
Histology of the Liver
Hepatic Cords of hepatocytes radiate from the central vein.
In the space between this space exist the bile canaliculi (cleft like lumen)
and
hepatic sinusoids (blood channels)
Hepatic Sinusoids
Vascular channels that recieve blood from the terminal branches of the hepatic artery and portal vein and drain to the central vein
Functions of the Liver
Secretion and production of bile.
Nutrient storage (vitamins, glycogen, fat, Cu & Fe)
Nutrient inter conversion
detoxification
What are the Six Components of Bile
Bile Acids Lecuthin Cholesterol Bile Pigments (billirubin) Toxic metals (detoxed in liver) Bicarboante (secreted by duct cells)
Where does the central vein drain to?
The central vein drains to the hepatic veins, into the IVC
Components of Bile synthesised in the liver and fat soluble
Bile Acids
Lecithin
Cholesterol
Bile pigment (bilirubin)
What is bilirubin composed of?
Made from breakdown products of haemoglobin from erythrocytes.
Synthesis of Bile acids
Synthesised from cholesterol. Before secretion, bile acids are conjugated with glycine or taurine.
Are bile salts reabsorbed?
Bile salts are recycled via portal circulation once they have carried out their role in micelle formation ( fat absorption)
The role of the gallbladder in bile salt concentration
The gallbladder removes water from bile salts to increase concentration
Control of Bile secretion
Sphincter of Oddi, relaxation allows bile and pancreatic fluid to enter the duodenum
Fat in duodenum triggers release of CCK. Relaxing the sphincter and contracting the gallbladder and discharges bile into the duodenum.
revisit powerpoint
What does CCK mean?
Cholecytokinin
