5.2.2 The Mammalian Liver: Structure Flashcards
What is the external liver structure?
The liver is involved with the breakdown of toxic substances and the production of excretory waste; in order to carry out these roles it requires a good blood supply
Oxygenated blood from the heart is carried to the liver via the hepatic artery; this provides oxygen for aerobic respiration, fuelling the metabolic activity of the liver cells
The liver receives blood from the digestive system via the hepatic portal vein; this allows it to absorb and metabolise nutrients that are absorbed into the blood in the small intestine
Deoxygenated blood exits the liver in the hepatic vein and flows back to the heart
The liver is also connected directly to the gall bladder, the role of which is to:
store bile, a liquid that contains:
bile salts for lipid digestion
bile pigments from the breakdown of haemoglobin
release bile into the duodenum via the bile duct
What is the internal liver structure?
The liver is mainly made up of cells known as hepatocytes; these cells carry out almost all the functions of the liver
The liver cells are arranged into structures known as lobules
Each lobule is supplied with blood by branches of the hepatic artery and the hepatic portal vein
The blood from the hepatic artery and portal vein mixes within each lobule inside wide capillaries known as sinusoids
Blood within the sinusoid exchanges substances with nearby hepatocytes, allowing the hepatocytes to perform all the functions of the liver
Each lobule is also connected to a branch of the hepatic vein that drains blood away from the lobule and into the main hepatic vein
Look at SME diagrams
