Liver Structure and Function Flashcards
Where is the liver located?
In upper right quadrant of abdomen
Describe anatomy of the liver
Right lobe is bigger than left
Has 2 minor lobes - caudate and quadrate
Porta on inferior surface with entry/exit vessels
Which vessels enter/exit the porta of the liver?
Hepatic portal vein
Hepatic artery
Lymphatic vessels
Right and left hepatic ducts into common hepatic duct
Hepatic nerve plexus
What does the common hepatic duct join with?
Cystic duct from gallbladder
What ducts make up the Sphincter of Oddi?
Common bile duct and pancreatic duct
Describe the bare area of the liver
Liver is covered by connective tissue capsule and visceral peritoneum except for here - surrounded by coronary ligament
Describe the septa of the liver
At porta - branching network into body of liver to provide support
Septa divide the liver into hexagonal lobules
What follows septa throughout liver?
Vessels, ducts and nerves
What is included in the portal triad?
Hepatic portal vein
Hepatic artery
Hepatic duct
Where is the portal triad located?
At each corner of the hexagonal lobule
What is at the centre of each hexagonal lobule?
Central veins at centre which drain to hepatic veins then IVC
What are hepatic cords?
Radiate out from central veins
Composed of hepatocytes which are the functional cells of the liver
What lies between each hepatic cord?
Canaliculus
What are hepatic sinusoids?
Spaces between the hepatic cords which are blood channels
Describe the journey of blood after going through the alimentary canal
Hepatic portal vein
Then to portal triad to hepatic sinusoids
Then to central veins
Then to hepatic veins
What is the blood like after leaving the alimentary canal?
O2 depleted
Nutrient rich blood
Describe the journey of the livers blood supply
Hepatic artery
Then hepatic sinusoids
Then central veins
Then hepatic veins
What is the blood for the livers blood supply described as?
O2 rich as hasn’t been through gut
Nutrient depleted blood
Describe the journey of bile in the liver
Hepatic sinusoids
Hepatocytes which synthesis bile
Then canaliculi
Hepatic ducts
What are some other functions of hepatocytes in the liver?
Bile synthesis
Nutrient storage - glycogen, fat, vits, Cu and Fe
Nutrient interconversion
Detoxification - adds protein
What is the alimentary role of the liver?
Production and secretion of bile
What are the 6 components of bile?
Bile acids
Lecithin
Cholesterol
Bile pigments
Toxic metals
Bicarbonate
Describe lecithin
Synthesised in the liver
Solubilises fat
What is the function of bicarbonate?
Neutraliser of acid chyme
What is secreted from hepatocytes?
Bile acids, lecithin, cholesterol, bile pigments and toxic metals
Where is bicarbonate secreted from?
Duct cells
What are bile pigments?
Breakdown products of haemoglobin form old/ damaged erythrocytes
What creates yellow bile?
Bilirubin extracted from blood by hepatocytes and secreted into bile
What makes faeces brown?
Bilirubin modified by bacterial enzymes to give brown pigment
What makes urine yellow?
Reabsorbed bilirubin excreted in the urine
How are bile acids synthesised?
In liver from cholesterol
How does bile acids become bile salts?
Before secretion bile acids are conjugated with glycine or taurine - increased solubility
How are bile salts recycled?
Enterohepatic circulation
Liver - bile duct - duodenum - ileum - hepatic portal vein - liver
What are the 3 wall layers of the gallbladder?
Mucosa - folded rugae
Muscularis - smooth muscle
Serosa - CT
What is the journey of bile out gallbladder?
Gallbladder - cystic duct - common bile duct
What is the function of the Sphincter of Oddi?
Controls release of bile and pancreatic juice into duodenum
If contracted then bile forced back into gallbladder
How much does the gallbladder concentrate bile?
5-20 times as absorbs Na and water
What causes the release of CCK?
Fat in the duodenum
What does CCK do once released?
Relaxes the sphincter of Oddi
Gallbladder contracts to release bile - fat solubilisation
Pancreatic enzyme secretion
Describe the function of secretin in the alimentary system
When acid is in duodenum - releases secretin from S cell
Causes decreased gastric acid secretion and gastric emptying
Increases duodenal and pancreatic bicarbonate causing neutralisation
