Liver structure and function Flashcards
How many lobes does the liver have?
4 - right, left, caudate and quadrate
Whats the largest lobe of the liver?
Right lobe
What makes up the portal triad?
Hepatic portal vein, hepatic artery and hepatic duct
What is the alimentary role of the liver?
Bile production
What are the 6 constituents of bile?
Bile acids – synthesised in hepatocytes, solubilise fat
Lecithin – synthesised in hepatocytes, solubilise fat
Cholesterol – synthesised in hepatocytes, solubilise fat
Bile Pigments - Bilirubin (from haemoglobin) most important
Toxic Metals – From diet, detoxified in liver and disposed into gut
Bicarbonate - Neutralisation of acidic chyme from stomach
What is the predominant bile pigment?
Bilirubin, from old haemoglobin
What are bile acids synthesised from?
Synthesised in liver from cholesterol (0.5g/day)
How are bile acids made into bile salts?
Before secretion, bile acids conjugated with glycine or taurine ==> Bile Salts (↑ solubility)
Why are bile acids converted into bile salts?
To increase solubility following secretion
How are bile salts recycled?
Secreted bile salts recycled via enterohepatic circulation
Describe briefly enterohepatic circulation
Liver ==> bile duct ==> duodenum ==> ileum ==> hepatic portal vein ==> liver etc
How do bile salts act as biologic detergents?
Bile salts are also biologic detergents that enable the body to excrete cholesterol and potentially toxic compounds (eg, bilirubin, drug metabolites). The function of bile salts in the duodenum is to solubilize ingested fat and fat-soluble vitamins, facilitating their digestion and absorption.
What are the three layers in the gallbladder wall?
- Mucosa (folded rugae, can allow expansion without stretching)
- Muscularis (smooth muscle) – contraction for bile expulsion
- Serosa (connective tissue) – as it is peritoneal cavity, protection
What controls the release of bile and pancreatic juice into the duodenum?
Sphincter of Oddi
What is the function of the gallbladder?
Gallbladder concentrates bile 5-20 times via the absorption of Na+, and H2O via large osmotic force created
