5.1.2 The Liver Flashcards
define excretion
the removal of metabolic waste products from the body
name three metabolic waste products
- carbon dioxide
- bile pigment (bilirubin)
- urea
similarities between excretion and secretion
both use ATP
both involved in homeostasis
products released by cells
differences between excretion and secretion
excretion- metabolic waste from cells s= useful products e=removal from the body s= released from glands e=no vesicles s=vesicles
what is the job of the hepatic vein
take deoxygenated blood away from the liver
what’s the job of the hepatic artery
DELIVERS OXYGENATED BLOOD FROM THE HEART
what’s the job of the hepatic portal vein
deoxygenated blood rich in digestion products from intestines to the liver
what can the lobes of the liver be further divided into
cylindrical lobules
what is a knupffer cell
a resident macrophage which live in the sinusoid, they break down old red blood cells to produce bilirubin ( a waste product of haemoglobin )
what’s the name for blood vessels which lead into the lobule
inter-lobular vessels (eg hepatic artery)
what’s the name for vessels leaving the lobule
intra-lobular vessels (hepatic vein)
what is bile
a greenish-brown alkaline fluid
aids digestion by breaking down fats into smaller droplets (emulsification)
what is bile secreted from and where is it stored
secreted by the liver and stored in the gall bladder
describe jaundice
causes yellow orange skin and eyes
symptom is white faeces
this is where the bile duct leaving the liver gets blocked so bile does not reach the digestive system and remains in the body
what is the purpose of deamination
to convert excess amino acids into ammonia as proteins cannot be stored
deamination is the removal of the amine group
what useful product is created in deamination
keto acids which are used in respiration to make ATP
what’s the name of the cycle that converts ammonia into urea
the ornithine cycle
describe the ornithine cycle
ammonia + C02 = citrulline
NH3 + citrulline= arginine
arginine + H20 = urea
name 3 other activities of the liver
1) the breakdown of toxic hydrogen peroxide by enzyme catalase ( 2H202 = 2H20 + 02 )
2) carbohydrate metabolism (glycogenolysis…)
3) detoxification of ethanol
describe the process of detoxification of alcohol
ethanol is converted into ethanal by ethanol dehydrogenase
ethanal is then converted into ethnic acid by ethanal dehydrogenase
ethnic acid is then converted into acetyl coenzyme A
this process involves the coenzyme NAD
why can you end up with a fatty liver
the liver prioritises hydrolysing ethanol over fatty acids, if the liver has too much alcohol to detoxify the fatty acids build up in the liver which can result in a fatty liver (hepatitis/ cirrhosis)
what is the advantage of the liver having a good blood supply
by products are able to enter the blood very easily
