the liver- excretion

Question 1

define excretion

Answer 1

removal of toxic waste products of metabolism and substances in excess requirement are removed from the body

Question 2

production of ammonia

Answer 2

-produced from the deamination of excess amino acids
-a Build of ammonia and CO2 can change body fluid pH, denaturing enzymes

Question 3

production of CO2

Answer 3

-decarboxylation of respiratory substrates in respiration

Question 4

production of urea

Answer 4

-ornithine cycle in liver cells
-if not removed can interfere with water potential=cell lysis

Question 5

production of bile pigments

Answer 5

-breaking down of haem groups of haemoglobin in liver cells
-if not removed can accumulate on the skin and turn it yellow (jaundice)

Question 6

hepatic portal vein vs hepatic vein vs hepatic artery

Answer 6

hepatic artery- oxygenated blood to the liver from heart
hepatic portal vein-deoxygenated blood from digestive system allowing the liver to absorb + metabolise diff nutrients
hepatic vein- deoxygenated blood from liver to heart

Question 7

liver and gall bladder link

Answer 7

-liver connected directly to the gall bladder (which stores bile containing bile salts and pigments)
-bile then released into duodenum via bile duct

Question 8

list the components that make up the liver + description

Answer 8

hepatocytes- (simple liver cells) large SA
sinusoids-wide capillaries lined with endothelial cells
bile canaliculus- bile flows from here to bile duct
-

Question 9

3 main roles of liver

Answer 9

-stores glycogen (converts glucose to glycogen/ glycogenesis)
-detoxification of lactate, hormones, alcohol, drugs etc
-formation of urea

Question 10

formation of urea

Answer 10

-excess amino acids are deaminated (amino group is removed NH2 and an extra hydrogen =ammonia, NH3)
-keto acid remains, can go to krebs
-ammonia + CO2 is converted to urea, less toxic and less soluble in orthenine cycle
-urea then diffuses through phospholipid bilayer of hepatocytes + transported to kidneys via blood plasma

Question 11

lactate metabolism

Answer 11

-produced in anaerobic respiration
-excess lactate absorbed into hepatocytes where it is converted to pyruvate
-some of this pyruvate goes to krebs to provide the energy needed to convert rest of lactate to glucose where it is either stored or enters blood to maintain blood conc

Question 12

alcohol metabolism

Answer 12

-alcohol/ ethanol absorbed by hepatocytes
-metabolism of ethanol produces lots of ATP, which is converted to fat and stored in the liver (fatty liver), slows the function of the liver

Question 13

hormone metabolism

Answer 13

Protein hormones (e.g. insulin and glucagon) and peptide hormones (e.g. anti-diuretic hormone) are hydrolysed into amino acids, which can then be converted to urea via deamination

Question 14

MAKE SURE TO STUDY LIVER UNDER MICROSCOPE AND PHOTOS