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12 Cards in this Set
- Front
- Back
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What are the following and their approximate values?
1) Renal Blood Flow? 2) Renal Plasma Flow? 3) Glomerular Filtration rate 4) The Filtration Factor |
1) Volume of blood that passes into the kidneys every minute: 1.1L/min
2) The amount of actual PLASMA that passes ( ie no RBC etc) that passes into the afferent arteriole per minute: 605 ml/min 3) Volume of plasma filtered into bowman's space per minute: 125ml/min 4) GFR divided by RPF |
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What structures form the filtration barrier (3)
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-Capillary endothelium
-Basement membrane -Podocyte layer |
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Why can't proteins be filtered
Bonus: up to what size in Kd can a protein be to be filteres |
Basment membrane carries positive charge whereas the basement membrane is negative. Filtration slits are too small.
Bonus: 5500Kd |
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What 3 pressure determine filtration
Which way do they "push" |
1) Hydrostatic in capillary (into tubule)
2) Hydrostatic in tubule (into capillary) 3) Osmotic (into capillary) |
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Define plasma clearance
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The volume of plasma from which any substance is completely removed (to the urine) by a kidney in a given amount of time
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1) What is the clearence for urea
2) In one minute therefore, how much is reabsorbed? |
1) 65ml/min
2) 60ml/min |
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1) What is the clearance for Inulin
2) What does this tell us about the nature of inulin handling in the kidney |
1) 125 ml/min
2) It is not reabsorbed at all |
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What would a clearance great than 125ml/min tell us?
Bonus: name a substance that behaves like this |
That that substance is being secreted into the filtrate by cells in the nephron
Bones: Para-amino hippurate (PAH) |
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What are the normal ranges of the following in the blood (turns out we have to know these see page 39 of handbook)
1) Na 2) K 3) HCO3 4) Urea 5) Creatinine 6) Calcium 7) pH |
1) Na 135-146 mmol/L
2) K 3.5 - 5.0 mmol/L 3) HCO3 22-30 mmol/L 4) Urea 2.5-6.7 mmol/L 5) Creatinine 79-118 μmoles/L 6) Ca2+ 2.20 - 2.67 mmol/L 7) pH 7.35-7.45 |
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How is GFR controlled with fluctuating systemic BP?
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By altering resistance in the eff/afferent arterioles supplying the glomerulus through vaso-constriction/dilatation
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Autoregulation: Describe the process to combat increased afferent arteriole pressure to regulate GFR starting from blood entering glomerulus at high pressure
(i've put a bit in brackets in the answer because it's bit detailed) |
High pressure - up hydrostatic pressure in glomerulus - up GFR - less Na gets reabsorbed in early nephron - more gets to DCT - (up Na leads to depolarisation - Calcium enters macula densa - smooth muscle constriction) - initiates vasoconstriction in afferent arteriole - down GFR
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Tubular secretion: describe the cellular mechanism of secretion of ions eg K+
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1) Na-K-ATPase creates Na gradient
2) Na moves into cell from lumen down gradient through Na-H antiporter 3) increased [H] in lumen 4) H+ moves back into cell through H+ - K+ exchanger (or whatever it is you're secreting) |
