Concentration and Dilution of Urine — Flashcards

Flashcard 1: Vasopressin escape in SIADH results due to downregulation of _____ production.

Answer: aquaporin 2

Flashcard 2: When CH2O is _____, urine is iso-osmotic relative to plasma

Answer: zero

Flashcard 3: Loop of henle is a countercurrent _____ and vasa recta is a countercurrent _____ in maintainence of osmolality gradient

Answer: multiplier; exchanger

Flashcard 4: The _____ and outer medullary collecting ducts are permeable to H2O and impermeable to urea (ADH present)

Answer: cortical

Flashcard 5: In the _____ nephrons, the peritubular capillaries give off vasa recta (straight arterioles) which run parallel to the loop of Henle

Answer: juxtamedullary

Flashcard 6: _____ diabetes insipidus is characterized by polyuria and polydipsia with an inability to concentrate urine due to lack of response to ADH

Answer: Nephrogenic

Flashcard 7: In the absence of _____, the principal cells of the late distal tubule and collecting duct are impermeable to water

Answer: ADH

Flashcard 8: The _____ and thick ascending limbs (loop of Henle) are permeable to Na+

Answer: thin

Flashcard 9: In the _____ of the nephron, urea is secreted by simple diffusion

Answer: thin descending limb (Henle's loop)

Flashcard 10: What is the formula for renal clearance ($C_x$)?

Answer: $C_x = \frac{U_x V}{P_x}$

Extra: $U_x$ = Urine concentration of X $P_x$ = Plasma concentration of X $V$ = Urine flow rate