RENAL Flashcards
What is the filtration unit of the nephron?
- Renal Corpuscle
What does the renal corpuscle comprise of?
- Glomerulus + Fluid filled bowmans capsule
What are the 3 processes involved in urine formation?
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
What is the renal blood vessel arrangement?
- Arteriole–> Capillaries–> arterioles–> Venules
Do plasma proteins normally filter through the glomerulus?
NO! Too large
What is the difference between fluid in the plasma and bowman’s capsule?
- Bowmans capsule is free of protein
In general, which of the 3 processes in urine formation would be active when glucose enters?
- Filtration, COMPLETELY reabsorbed, NOT SECRETED
In general which of the 3 processes of urine formation would be active with many electrolytes (ions)?
- FIltration, SOME absorption and NO SECRETION
Which force drives filtration?
- Hydrostatic pressure and large finestrations (high permeability)
What are the 3 layers of the glomerular filtration barrier? (inside–> out)
- Single celled capillary endothelium (pores/finestrae)
- Non-cellular basement membrane
- Single celled epithelial lining of Bowmans capsule (podocytes and filtration slits)
What happens to the filtrations between endothelial cells in kidney failure?
- Become clogged, so can’t filter well (also in diabetes)
Are waste products well absorbed?
-No!
Are ions well absorbed?
- YES! Important to the body
How much filtrate is taken back into body?
- 99%
What is the equation for excretion?
- Excretion=Filtrate- (re absorption + Secretion)
Is glucose 100% reabsorbed normally?
- YES!
Is sodium or water reabsorbed more in general? -
- Sodium (99.5%) compared to H20 (99%)
What is GFR?
- Glomerular filtration rate
- Volume of filtrate formed from kidney each minute (ml/min)
What is the normal GFR?
- 125ml/min (180L/day)
What would happen without tubular reabsoprtion?
- Whole plasma volume (3L) and essential solutes would be excreted within 30MINS
What would happen in the body if GF continued normally, but tubular reabsorption decreased to 50% of normal rate?
Excretion would increase
In tubular reabsoprtion, which two pathways can solutes take?
- Transcellular (through cells)
- Paracellular (through tight junctions)
What is the transcellular pathway for tubular reabsorption?
- Luminal membrane –> cytosol—> Basolateral membrane –> interstitial fluid–> Endothelial cells–> Plasma of peritubular capillareis
Is reabsorption of H20 secondary to Na+?
YES! Most of energy goes into reabsorbing sodium