Renal 6 Flashcards
What creates the hyperosmotic interstitium?
- countercurrent exchange system
- urea
Two components of the renal countercurrent exchange system
- countercurrent multiplier
- countercurrent exchanger
countercurrent multiplier
the loop of henle; create hypertonic interstitium
countercurrent exchanger
the peritubular capillaries (vasa recta); prevent the washout (dilution) of the hypertonic interstitium
Descending limp of loop of henle
allows water to follow its osmotic gradient into increasingly hypertonic interstitium, but does not allow solutes to be transported
the ascending limb of the loop of Henle
actively transports solutes (Na+, Cl-, K+) into the interstitium
Active reabsorption of ions in the apical surface of the ascending limb creates a dilute filtrate in the lumen because….
it’s not permeable to water
NKCC2 transported
uses energy stored in the Na+ conc. gradient to move Na+, K+, and 2 Cl- into the epithelial cells
About half the solute in the medulla interstitium is..
urea
high AVP increases AQP2 insertion, therefore…
increased reabsorption
low AVP result in decreased AQP2, therefore…
reduced reabsorption
WHAT MAINTAINS OUR MASS BALANCE?
homeostatic mechanisms
The kidneys are responsible for most ____ excretion
Na+; very little lost to perspiration and in feces
