5.1.2 The Liver

Question 1

define excretion

Answer 1

the removal of metabolic waste products from the body

Question 2

name three metabolic waste products

Answer 2

• carbon dioxide
• bile pigment (bilirubin)
• urea

Question 3

similarities between excretion and secretion

Answer 3

both use ATP
both involved in homeostasis
products released by cells

Question 4

differences between excretion and secretion

Answer 4

excretion- metabolic waste from cells 
s= useful products
e=removal from the body
s= released from glands
e=no vesicles
s=vesicles

Question 5

what is the job of the hepatic vein

Answer 5

take deoxygenated blood away from the liver

Question 6

what’s the job of the hepatic artery

Answer 6

DELIVERS OXYGENATED BLOOD FROM THE HEART

Question 7

what’s the job of the hepatic portal vein

Answer 7

deoxygenated blood rich in digestion products from intestines to the liver

Question 8

what can the lobes of the liver be further divided into

Answer 8

cylindrical lobules

Question 9

what is a knupffer cell

Answer 9

a resident macrophage which live in the sinusoid, they break down old red blood cells to produce bilirubin ( a waste product of haemoglobin )

Question 10

what’s the name for blood vessels which lead into the lobule

Answer 10

inter-lobular vessels (eg hepatic artery)

Question 11

what’s the name for vessels leaving the lobule

Answer 11

intra-lobular vessels (hepatic vein)

Question 12

what is bile

Answer 12

a greenish-brown alkaline fluid

aids digestion by breaking down fats into smaller droplets (emulsification)

Question 13

what is bile secreted from and where is it stored

Answer 13

secreted by the liver and stored in the gall bladder

Question 14

describe jaundice

Answer 14

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

Question 15

what is the purpose of deamination

Answer 15

to convert excess amino acids into ammonia as proteins cannot be stored
deamination is the removal of the amine group

Question 16

what useful product is created in deamination

Answer 16

keto acids which are used in respiration to make ATP

Question 17

what’s the name of the cycle that converts ammonia into urea

Answer 17

the ornithine cycle

Question 18

describe the ornithine cycle

Answer 18

ammonia + C02 = citrulline
NH3 + citrulline= arginine
arginine + H20 = urea

Question 19

name 3 other activities of the liver

Answer 19

1) the breakdown of toxic hydrogen peroxide by enzyme catalase ( 2H202 = 2H20 + 02 )
2) carbohydrate metabolism (glycogenolysis…)
3) detoxification of ethanol

Question 20

describe the process of detoxification of alcohol

Answer 20

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

Question 21

why can you end up with a fatty liver

Answer 21

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)

Question 22

what is the advantage of the liver having a good blood supply

Answer 22

by products are able to enter the blood very easily