Renal Nephron Physiology Flashcards
DCT:
No Brush border, no canaliculi or lysosomes
Parts of the nephron:
Glomerulus, Bowman’s capsule, PCT, Loop of Henle, DCT.
NO collecting duct
JGA contains what sort of cells and what do they monitor
JGA contains macular densa cells, monitor Na+ levels about to enter DCT, secrete renin.
What drug targets the PCT
Acetazolamide - carbonic anhydrase
At the PCT, what % of H2O, Na+ and HCO3 etc.
65% H2O and Na+ 50% Cl 80-90% HCO3- >90% K+ Glucose, AA and lactose
What pumps are found at PCT
Na/H+ ATPase at basolateral membrane
What is absorbed at thin descending and thick ascending limb in Loop of Henle?
Thin descending: water reabsorbed, no active Na+ reabsorption.
Thick ascending: reabsorbs 25% of filtered NaCl, K+, Cl- (Na/K/2Cl symport), Ca2+ and (10%) HCO3-.
Frusemide acts here!
Filtrate begins isoosmotic and finishes hypoosmotic
DCT: histology, what is reabsorbed/secreted?
No brush border or apical canaliculi - intercalated cells (acid and base)
macula densa.
Impermeable to water.
Reabsorption of NaCl, Ca2+ and HCO3- (Na/Cl symporter)
Secretion of K+ (Na/K ATPase)
Collecting duct features:
Not part of nephron, joins with other nephrons to becone uriniferous duct.
Normally impermeable to water, but ADH can act on AQP-2 to increase reabsorption of water.
Where does frusemide act:
At thick ascending loop at Na/K/2Cl symport.
Where does carbonic anhydrase inhibitor (acetazolamide) act?
At PCT at Na/H exchanger luminal (urine side) membrane - prevent acidification of tubular lumen.
Where does thiazide act?
Thiazide acts at the DCT blocking the action of Na/Cl- transporter.
Where does spironolactone act?
At distal tubule/collecting duct: aldosterone antagonist at principal cells.
Results in hyperkalaemia, impotence, menstrual disturbances.
Where does amiloride act?
At DCT - acts as a Na+ channel blocker - principal cells
PCT: Type of cell
Apical surface
Basolateral surface
Simple squamous or cuboidal
Apical surface with brush border
Basal cytoplasm abundant in mitochondria
