Physiology 2 Flashcards
The thin descending loop of Henle is impermeable to _______, and thus reabsorbs _______.
sodium, water
The thin descending Loop of Henle absorbs water b/c of medullary _______.
hypertonicity
The thick ascending loop of Henle is impermeable to _______, and thus reabsorbs _______.
water; Na+, K+, and Cl- (directly) and Mg++ and Ca++ indirectly.
What kind of transport brings Na+, K+, and Cl- into the epithelial cells of the ascending loop of Henle from the tubular lumen?
Active cotransport
How do Mg++ and Ca++ get reabsorbed from the lumen of the ascending Loop of Henle?
They diffuse in between the cells due to a positive charge (+7 mV) inside the lumen.
What are the effects of PTH on tubular reabsorption? (2 segments)
Blocks Na+/phosphate cotransport @ PCT.
Increases Na+/Ca++ exchange @ DCT.
There is a renal tubular transporter on which Thiazide diuretics and Ang II have opposite effects. What is it and where is it located?
Na+/Cl- cotransporter in the DCT
Site of action of furosemide.
Na+/K+/Cl- cotransporter in the TAL
Aldosterone and potassium-sparing diuretics have opposite actions on the same channel. What channel is this and where is it located?
Na+ channel (ENaC) in the principal cells of the collecting tubule
What are the (2) aldosterne antagonist K+-sparing diuretics?
Spironolactone and eplerenone
What are the ENaC inhibiting K+-sparing diuretics?
Amiloride and Triamterene
How does ADH work?
Causes the insertion of aquaporins into the luminal membrane of collecting tubule epithelial cells.
What percentage of Na+ is reabsorbed at the PCT?
65-80%
What percentage of Na+ is reabsorbed at the TDL
0%
What percentage of Na+ is reabsorbed at the TAL?
10-20%
