Renal Physiology: Urinary Concentration and Dilution Flashcards
Hyposmotic body fluids create a ________ urine
dilute, (50 mOsm/L)
Hyperosmotic body fluids create a ______ urine
concentrated (1200 mOsm/L)
Can the kidneys regulated water excretion independently of solute excretion?
yes
The countercurrent multiplier ensures high concentration gradient from ________ to the _________
corticomedullary border (proximal descending loop)
to the (papilla)
The osmotic gradient in the ISF from the cortex to the medulla is used to do what?
remove water from urine in the collecting duct
This portion of the loop of henle has the following characteristics…
- no active transport of NaCl
- very water permeable
Descending limb
This portion of the loop of henle has the following characteristics…
- Increases in thickness
- actively reabsorbs NaCl
- impermeable to water
ascending limb
by what mechanism is NaCl pumped form the ascending limb?
active transport
What is the largest possible gradient across the wall of the ascending limb?
200 mOsm
What is the essential component to maintaining the countercurrent multiplier?
active transport of sodium and chloride ions
What is meant by “countercurrent” in countercurrent multiplier
flow of current occurs in opposing direction through the two limbs
What transporter present in the thick ascending limb of the LOH is responsible for active transport of ions from the ascending limb to the interstitium?
Na+, K+, 2Cl- transporter (NKCC2)
what blocks the NKCC2 receptor, leading to duresis?
furosemide
What stimulates NKCC2 leading to antiduresis?
ADH
What ensures that the renal blood flow doesn’t wash away the concentrated solute in the medullary ISF?
Countercurrent exchange in the vasa recta
Is the countercurrent exchange in the vasa recta active or passive?
passive
As blood flows down a hairpin loop of vasa recta, what occurs? What about the ascending part of the hairpin?
NaCl into capillary
H20 diffused out of capillary
opposite for ascending
the early distal convoluted tubule has what kind of transporter?
NaCl transporter NCC
NCC transporter is blocked by what?
thiazide diuretics
The early portion of the distal tubule is impermeable to what?
water
What is the osmolarity of the early distal convoluted tubule?
50 mOsm
The late distal tubule and collecting dict have what two cell types?
Principal cells
Alpha intercalated cells
This cell type in the late distal tubule has the following characteristics…
Reabsorbes Na+
Secretes K+
Site of aldosterone action
Site of ADH action
principal cells
This cell type in the late distal tubule has the following characteristics…
Secretes H+
Reabsorbes K+
Alpha intercalated cells
