The liver Flashcards
How is blood supplied to the liver?
via the hepatic artery and hepatic portal vein
Which vessel carries blood loaded with products of digestion from the intestine to the liver?
hepatic portal vein
What are liver cells called?
hepatocytes
What are specific features of hepatocytes?
large nuclei, prominent golgi apparatus and lots of mitochondria
What is a sinusoid?
spaces in the liver tissue surrounded by hepatocytes where blood from hepatic artery and hepatic portal vein mix
What are sinusoids surrounded by?
hepatocytes
What other cells do the sinusoids contain?
kupffer cells
What is the role of kupffer cells?
they act as resident macrophages to the liver by ingesting foreign particles and helping protect against disease
What do the hepatocytes secrete and where does it go?
bile secreted into spaces called canaliculi where it drains into bile duct which takes it to the gall bladder
What is bile made from?
the breakdown of blood
What are the three main functions of the liver?
deamination of excess amino acids, detoxification and carbohydrate metabolism
How does the liver control blood glucose levels?
rise in insulin levels cause hepatocytes to convert glucose to glycogen to be stored and vice versa with glucagon
What is transamination?
the conversion of one amino acid to another
Why is transamination important and which cells do it?
important because our diet doesn’t always contain the required balance of amino acids so they can be changed by the hepatocytes
What is deamination?
the removal of the amine group from excess amino acids
Why is deamination important?
the body cannot store proteins or amino acids so excess is excreted which is a waste
What happens to the amine group in deamination?
converted to ammonia then to urea which is excreted by the kidneys
Briefly describe the ornithine cycle?
series of reactions converting ammonia to urea. ammonia + CO2 gives citruline. citruline converts to arginine which loses water to turn into urea
How is hydrogen peroxide broken down?
hepatocytes contain the enzyme catalase which splits hydrogen peroxide into water and oxygen
How does the liver detoxify ethanol?
hepatocytes contain alcohol dehydrogenase which breaks down ethanol into ethanal which is converted into ethanoate which can be used to build up fatty acids or used in respiration
Which two important enzymes for detoxification do hepatocytes contain?
alcohol dehydrogenase and catalase
