Liver - Structure and Function Flashcards
Where is the liver located?
Upper right quadrant against inferior surface of diaphragm
What are the 2 major lobes?
Left
Right
What are the 2 minor lobes?
Caudate
Quadrate
What structures enter/exit via the porta on the inferior surface of the liver?
Blood vessels
Lymphatic vessels
Ducts
Nerves
What blood vessels go through the porta?
Hepatic portal vein
Hepatic artery
Which ducts go through the porta?
Right and left hepatic ducts
What nerves go through the porta?
Hepatic nerve plexus
What 2 ducts form the common bile duct?
Common hepatic duct
Cystic duct
What 2 ducts enter the major duodenal papilla?
Common bile duct
Pancreatic duct
Whats another name for the major duodenal papilla?
Sphincter of Oddi
How is the liver covered?
Connective tissue capsule
Visceral peritoneum
What is the bare area of the liver?
Small area of liver next to diaphragm with no peritoneum
Covered by coronary ligament
What happens to the connective tissue capsule at the porta?
Branches network of septa into the body of the liver for support
What shape does the septa divide the liver?
Into hexagonal lobules
What makes up the portal triad?
Hepatic portal vein
Hepatic artery
Hepatic duct
Where is the portal triad?
Located at each corner of hexagonal lobules
Where are central veins located?
At the centre of each lobule
Where does the central veins drain to?
Hepatic veins –> IVC
What attaches the liver to the diaphragm?
Coronary ligament
What are hepatic cords?
Composed of hepatocytes
Radiate out from central veins
What lies between cells within each cord?
Bile canaliculus
What is bile canaiculus?
Open channel that runs up the centre in between cells
What are the spaces between hepatic cords?
Hepatic sinusoids (blood channels)
What type of capillaries does the liver have?
Discontinuous
What are the functions of hepatocytes?
Bile synthesis
Nutrient storage
Nutrient interconversion
Detoxification
What is the only nutrient that the gut regulates?
Iron
What happens when the liver has reached its maximum storage limit for glycogen?
Liver converts glucose into other sources of energy (e.g. fat)
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
What do bile acids, lecithin and cholesterol do?
solubilise fat
synthesised in the liver
What happens to toxic metals in the liver?
They are detoxified
What does bicarbonate do?
Neutralises acid chyme
Out of the 6 components of bile, which is not secreted by hepatocytes and what secretes it?
Bicarbonate
Secreted by duct cells
What are bile pigments?
Breakdown products of haemoglobin from old/damaged erythrocytes
Where does yellow bile come from?
Bilirubin extracted from blood by hepatocytes and secreted into bile
Where does brown faeces come from?
Bilirubin modified by bacterial enzymes to form brown pigments
Where does yellow urine come from?
Reabsorbed bilirubin excreted in urine
How are bile acids synthesised?
In liver from cholesterol
What happens with bile acid before secretion?
Bile acids conjugated with glycine or taurine to form bile salts which increases solubility
What is secreted bile salts recycled?
Via enterohepatic circulation
liver - bile duct - duodenum - ileum - hepatic portal vein - liver
What happens when bile is not required?
It is stored in the gallbladder and released when needed
What are the 3 layers in the wall of the gallbladder?
Mucosa
Muscularis
Serosa
What is role of mucosa in the gallbladder?
Folded into rugae for expansion
What is the role of muscularis in the gallbladder?
Smooth muscle for contraction
What makes up the serosa of the gallbladder?
Connective tissue
What is the role of the sphincter of Oddi?
Controls release of bile and pancreatic juice into the duodenum
What happens when the sphincter of oddi is closed?
Bile is forced back into the gallbladder
What does the gallbladder do to bile?
Concentrates bile 5-20 times
What is triggered with fat in the duodenum?
Release of CCK
What does the release of CCK do?
Causes sphincter of oddi to relax and gallbladder contracts
Causes pancreatic enzyme secretion and bile secretion
