Liver

Question 1

Liver blood supply

Answer 1

Hepatic portal vein = where blood goes from the small intestine to the liver (low O2, and variable nutrients)

Hepatic vein = liver to the heart, low O2 but consistent nutrients since the Liver metaboilises the waste

Hepatic artery = heart to the liver, high O2, consistent nutrients

Question 2

portal triads

Answer 2

consist of the hepatic artery, the hepatic portal vein and the hepatic/bile duct

blood supply and waste removal

Question 3

liver lobule and central vein

Answer 3

the central vein is in the midle of the livver lobule

Question 4

glucose homeostasis

Answer 4

glucagon is released when glucose levels are low
insulin is released when glucose levels are high
stores glucose as glycogen in the liver

Question 5

cholesterol balance

Answer 5

the liver synthesises cholesterol
LDL and HDL carry different types of cholesterol
the liver is involved to make VLDL (very low density lipoprotein) and LDL (low density lipoprotein)
-> LDL cholesterol can cause plaques in the blood
produces HDL to bring the cholesterol in blood vessels back to the liver
excretes the excess cholesterol as bile and removed as faeces or as bile acid for digestion

Question 6

Albumin

Answer 6

==osmolarity
albumin is a protein made by the liver
it is a large protein so cannot leave the blood vessels
creates a water potential gradient between the blood and the tissues and water goes into the blood
prevents excess tissue fluid in tissues (edema)

==water insoluble molecules transport
albumin also has hydrophobic regions, allows water-insoluble molecules to attach and get transported in the bloood

Question 7

coagulation factors

Answer 7

produced by the liver
a blood protein involved in healing
–>Damage results in a cascade
of reactions, which involves most of the proteins made by
the liver

Question 8

amino acid metabolism

Answer 8

deamination, the NH2 group are removed from amino acids == keto acid
the NH2 (amine group) == NH3 (ammonia)
NH3 is toxic –> urea

Question 9

pH balance

Answer 9

liver produces bicarbonate (HCO3-) == can neutralise acid
–> urea synthesis can use up the bicarbonate

ketogenesis lowers ph (products are acidix)

metaboilising lactic acid = liver converts lactic acid into glucose, higher pH, produces HCO3- and H+ decreases, neutralise excess acid in the blood

Question 10

Some major neurotransmitters in humans

Answer 10

serotonin = mainly released by the gastrointestinal system (mood)
oxytocin = love hormone : trust, maternal behaviour, huggies etc –> not good for animals to ‘trust’ so liver metaboilises it
oestrogen = main female sex hormone
testosteron = main male sex hormone

Question 11

caffeine

Answer 11

liver metabolises it by removing at least one methyl group of caffeine
=paraxanthine
=theobromine
=theophyline
uses the enzyme group (group of enzymes) cytochrome CYP1A2 in the oxidation reactions to catalyse the breakdown and metabolism of caffeine

Question 12

alcohol

Answer 12

ethanol is metabolised with alcohol dehydrogenase
–> acetylaldehyde
acetylaldehyde is toxic
metaboilised into acetate using aldehyde dehydrogenase
to form acetate/acetic acid
acetate –> blood stream into the kerbs cycle in cells
–> produces CO2 + H2O

Question 13

Pathogens

Answer 13

the blood from gut contains a lot of bacteria
liver contains specialised cells to destroy bacteria and virus
–»blood that leaves liver is very clean
–> makes sure the heart wont be contaminated

Question 14

RBCs

Answer 14

old RBCs breakdown to form bilirubin
– taken up by the liver cells
– forms water soluble compounds with other molecules
– excreted by the body through bile

Question 15

iron balance

Answer 15

iron is important in the body but free iron (iron not used = excess) is toxic
free iron is stored in the liver in a protein complex called ferritin
transferrin(protein) is produced when iron levels are low to transport the iron by binding to the iron in the ferritin complex in the liver to the rest of the body

Question 16

bile / gall

Answer 16

produced in the liver and stored in the gall bladder
–> needed in digestion and absorption of FATs in the SL (small intestine)

bilary excretion : toxic and waste products are disposed in to the bile and then sent to the gut to be removed

Question 17

movement of bile

Answer 17

bile is produced in the liver, —–> (hepatic ducts) —> common hepatic ducts
the common bile duct is the formation of the common hepatic and cystic ducts
the cystic ducts is connected to the gallbladder
common bile duct takes the bile to the small intestine