Kidney

Question 1

Early PCT function? How doe PTH impact it?

Answer 1

• Reabsorbs all glucose and AA’s
• Reabsorbs most HCO3, Na, Cl, PO4, K, uric acid and water
• Generates and secretes NH3 allowing kidney to secrete more H
• PTH inhibits Na PO4 transport increasing PO4 excretionl
• Acetazolamide and mannitol work here

Question 2

Thin descending loop of henle function?

Answer 2

• passively reabsorbs water via medullary hypertonicity
• Concentrating segment making urine hypertonic

Question 3

Thick ascending loop of henle? Diuretic?

Answer 3

• reabsorbs Na K and Cl
• Indirectly induces paracellular reabsorption of Mg and Ca through lumen potential made by K back leak
• Impermeable to water
• Makes urine less concentrated as it ascends
• Loop diuretics work here

Question 4

Early DCT? Diuretics and PTH effects?

Answer 4

• Reabsorbs Na and Cl
• impermeable to water
• makes urine fully dilute (hypotonic)
• PTH increases Ca/Na exchanger increasing Ca reabsorption
• Thiazide diuretics work here

Question 5

Collecting tubule?

Answer 5

Reabsorbs Na in exchange for secerting K and H

Aldosterone acts on MR receptro

ADH acts at V2 recewptor inserting aquaporin channels on apical side

Question 6

Fanconi syndrome

Answer 6

• Reabsorption defect in PCT leading to increased excretion rather than absorption of glucose, AA’s, bicarb and phosphate
• Can lead to metabolic acidosis, hypophosphatemia, and osteopenia

Question 7

Bartter syndrome?

Answer 7

• Reabsorption defect in thick ascending limb affecting the NKCC2 transporter
• Metabolic alkalosis hypokalemia and hypercalciuria
• AR inheritance, presents similarly to chronic loop diuretic ure

Question 8

Gitelman syndrome

Answer 8

• Reabsorption defect of NaCl In DCT
• Metatbolic alkalosis, hypomagnesmia, hypokalemia, hypocalciuria
• AR inheritance
• Presents similar to life long thiazide use
• Less sever ethan bartter syndrome

Question 9

Liddle syndrome?

Answer 9

• Gain of function mutation decreasing Na channel degradation leading to increased Na reabsorption in the collecting tubules
• Metabolic alkalosis, hypokalemia, htn, and decerased aldosterone
• AD inheritance
• Presents ismilar to hyperaldosteronism but aldosterone is undetectable
• Tx with amiloride

Question 10

AT II effects on kidnehy?

Answer 10

• Made in response to low BP
• Causes efferent (exit) arteriole constriction increasing GFR and FF
• Results overall in preservation of renal function (FF) in low volume states with simultaneous Na reabsorption to maintain volume

Question 11

ANP effect on kidney?

Answer 11

• Made in response to increased Atrial pressure
• causes Increased GFR and IncreasE d Na filtartion with no compensatory Na reabosption in distal nephron
• Overall results in Na loss and volume loss