Liver structure, function and pathologies Flashcards
What percentage of body weight is the liver
2-3%
What are the lobes of the liver
Major lobes: Right>left
minor lobes: caudate, quadrate
What joins the right and left lobe anteriorly and posteriorly
Falciform ligament–> anterior, lesser omentum: posteriorly
What makes up the Porta
Hepatic artery, portal vein and hepatic duct
What are the categories of cells in the liver
Parenchymal, non-parenchymal cells, Cholingiocytes
what are parenchymal cells
Hepatocytes: polarised (2 membranes), basolateral membrane face sinusoidal epithelium cells of capillaries.
What are cholangiocytes
biliary epithelial cells. Bile canaliculi passage way of bile from hepatocytes to bile duct.
Liver blood supplies
Portal blood: portal vein, high in nutrients low in oxygen.
Hepatic artery: high oxygen, low nutrients
Blood pathway into and out of liver
Hepatic artery + portal vein -> central vein–>hepatic vein –> IVC
What is the functional unit of the liver?
Hepatic lobule. Hexagonal shape with portal triad on each corner.
What makes up the portal triad
Portal vein, hepatic artery, bile duct and nerves and lymph vessels
what connects the portal triad to the central vein
hepatocyte cords made of hepatocytes, with sinusoids surrounding them and bile canaliculus between cells.
Direction of flow of bile and blood in hepatic lobule
bile moves from the centre outwards, and blood moves from outside towards the central vein.
Bile constituents
Bile acids, lecithin, cholesterol, bilirubin, toxic metals and bicarbonate
what bile constituents solubilize fat?
Bile acids, lecithin and cholesterol
Where are all the bile constituents secreted?
All are secreted in the liver except bicarbonate which is secreted from duct cells.
Function of bicarbonate
Neutralisation of acid chyme
What is the bile pigment
Bilirubin
How is bilirubin formed
breakdown of haemoglobin from old/damaged erythrocytes
Pathway of bile after breakdown and colour
secreted into bile from blood=yellow bile, bile–>intestines: bilirubin then modified by bacteria in the intestines=brown faeces. reabsorbed bilirubin excreted in urine=yellow urine.
What is the enterohepatic circulation
“bile’s journey”
liver–>bile duct–>duodenum–>ileum–>hepatic portal vein–> liver
How much bile salts are produced each day
0.5g/day and 95% of bile salts/acids are reabsorbed
what are conjugated bile salts
bile acids that have bound to taurine, glycine or sulphate in the liver before passing through the bile duct. this increases water solubility.
what happens to bile salts in the intestines
bacteria degrades the bile salts (–>acids), and they become less hydrophilic and are reabsorbed into the blood
