Excretion Flashcards
Summary
3 liver functions
+bonus
Ornithine cycle (ammonia + C02->urea + water)
Detoxification (ethanol->ethanal->acetic acid)
Stores glycogen
Extra: Glycogenesis and glyogenolysis
Role of hepatic artery
Role of hepatic portal vein
Role of bile duct
Supplied oxygenated blood
Brings production of digestion to hepatocyte
Take bile to gall bladder
What gets ultrafiltered at Bowman’s capsule
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What is selectively reabsorbed and where?
What’s to large for ultra filtration?
Water, glucose, sodium, urea
Water -> collecting duct
Glucose -> PCT
Sodium -> Loop of Henlé
Urea not selectively reabsorbed
Protein
How does ultra filtration take place?
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Efferent arteriole has smaller diameter than afferent arteriole
Creates hydrostatic pressure gradient
Molecules diffuse down gradient into capsule
How the Bowman’s capsule regulates molecules in….
Capillary endothelium
Basement membrane
Bowman’s capsule Podocytes
1) fenestrations between cells let small molecules through
2) collagen fibres prevent large molecules passing
3) major processes allows small molecules through
How to distinguish between renal artery and renal vein?
Renal artery wall thicker
Outline counter current multiplier system.
What diffuses out? Where?
What is descending loop of Henlé impermeable to?
What ‘potential’ decreases in the medulla?
How and why does what we re-enter?
Na+ actively pumped out of descending loop of Henlé
Descending loop of Henlé is impermeable to
Water
Decreases water potential of medulla
Water selectively reabsorbed into medulla via osmosis down concentration gradient at ascending loop of Henlé
Low blood water potential system.
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Osmoreceptors in hypothalamus detect low water potential
Signal sent to posterior pituitary gland to secrete more ADH
ADH binds to receptors on collecting duct plasma membrane via exocytosis
Makes it more permeable to water(more water selectively reabsorbed)
How does ADH control collecting duct permeability?
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ADH binds to receptors on collecting duct plasma membrane
Causes vesicles with aquaporins to bind to collecting duct membrane wall
Increases selective reabsorption of water
Pros and cons of kidney transplant
4 pros
3 cons
+saves life
+more convenient
+no dietary requirements
+Cheaper than dialysis in long run
- hard to find donor
- operation is risky and can cause death
- organ can be rejected by immune system
Pros and cons on dialysis
4 each
+helps patient live as they wait for transplant
+can eat what they want during dialysis
+completed by professionals
+can select appointments
- time consuming (inconvennient)
- dietary regulations
- costly in long run
- patient may feel unwell between sessions
How is Gas chromatography in drug testing done?
▪▪▪
Sample vapourised
Passed through column containing polymer
Substances separated out as they move at different speeds
