17.11 Physiology: Kidney function and electrolyte balance Flashcards
(17 cards)
How does water move out of the tubule?
Osmotically, bulk flow
What do the early and late PT specifically reabsorb?
Early: bicarb
Late: chloride
What is the voltage in the lumen of the late PT?
+3 mV (due to Cl concentration)
What is the Na reabsorption like in the early and late PT?
Early PT: negative lumen voltage, little Na reabsorbed
Late Pt: Na outflow, 50% paracellular, 50% trans-cellular
How is Na+ reabsorbed in the thin ascending limb?
Via passive diffusion across tight junctions (paracellular)
What do thiazides target?
NaCl co-transporter (distal covoluted tubule)
What do loop diuretic target?
Na/K/2Cl co-transporter
What does Amiloride target?
Epithelial sodium channel (collecting duct)
What is Frusemide often given with?
K+ supplements
How is Na reabsorbed in the distal tubule?
Completely by transcellular route
What do the waste products/xenobiotics use to enter late PT cells?
Roat1 (organic anion exchanger)
How do we retain H+ on the basolateral membrane?
MCT
How do we retain Na+ on the apical membrane?
NaDC1
What is the difference between the ascending/descending limb at any point (before multiplication)?
200mOsM
What inserts aquaporins?
ADH
Where does aldosterone get released from? What does this do?
From adrenal cortex, increases sodium reabsorption (distal tubule)
What does Ang II do in the kidneys? (3)
Constricts efferent arteriole (increase GFR)
Increases proximal tubule sodium reabsorption (upregulation of Na/H+ exchanger)
Acts on mesangial cells on glomerulus to contract(regulate GFR)
