Nephron Physiology

Question 1

PTH effects on proximal convoluted tubule

Answer 1

Inhibits Na/PO4 cotransport; Phosphate excretion

Question 2

AngII on proximal convoluted tubule

Answer 2

Stimulates Na/H exchange; Reabsorbs Na, H2O, and HCO3-

Question 3

65-80% of Sodium Reabsorbed

Answer 3

Proximal Tubule

Question 4

Tonicity of Proximal Tubule

Answer 4

Isotonic

Question 5

Reabsorbs all of the glucose, AA and most of HCO3, Na, Cl, PO4, K and H2O

Answer 5

Proximal tubules

Question 6

Passive reabsorbs H2O via medullary hypertonicity; impermeable to Na. Concentrating segment making urine hypertonic

Answer 6

Thin descending loop of Henle

Question 7

Indirectly induces paracellular reabsorption of Mg and Ca; potential is generated by K

Answer 7

Thick ascending limb of Henle

Question 8

Impermeable to H2O

Answer 8

Thick ascending limb of Henle

Question 9

Reabsorbs Na/K/2Cl

Answer 9

Thick ascending limb of Henle

Question 10

10-20% Na reabsorbed

Answer 10

Thick ascending limb of Henle

Question 11

Actively absorbs NaCl and makes urine hypotonic

Answer 11

Early distal convoluted tubule

Question 12

PTH effects on Early distald Convoluted tubule

Answer 12

Increases Calcium reabsorption with Ca/Na-exchange

Question 13

5-10% Na reabsorbed

Answer 13

Early Distal Convoluted tubule

Question 14

Reabsorbs Na in exchnage for secreting K and H

Answer 14

Collecting tubules, in response to aldosterone

Question 15

Insertion of sodium channel on luminal side

Answer 15

Aldosterone, collecting tubule

Question 16

V2 receptor

Answer 16

ADH in collecting tubule

Question 17

Inserts aquaporin H2O on luminal side

Answer 17

ADH in collecting tubule

Question 18

3-5% Na reabsorbed

Answer 18

Collecting tubule

Question 19

Block ENaC in Collecting tubule

Answer 19

Amiloride, Triamterene

Question 20

Thiazide Diuretics

Answer 20

Block Na/Cl cotransporter in Early convoluted tubule

Question 21

Loop Diuretics

Answer 21

Blook Na/K/2Cl channel in TAL

Question 22

Reabsorptive defect in PCT; associated with increased excretion of nearly all amino acids, glucose, HCO3-, and PO4

Answer 22

Fanconi Syndrome

Question 23

Causes of Fanconi Syndrome

Answer 23

Hereditary defects like Wilson dx, ischemia, and nephrotoxins/drugs

Question 24

Reabsorptive defect in TAL; affects Na/K/2Cl cotransporter causing hypokalemia, metabolic alkalosis with hypercalciuria

Answer 24

Bartter Syndrome (autosomal recessive)

Question 25

Resorptive defect of NaCl in DCT; leads to hypokalemia and metabolic alkalosis without hypercalciuria

Answer 25

Gitelman Syndrome (autosomal recessive)

Question 26

Increased Na reabsorptionin distal and collecting tubules by increasing ENaC. Causes HTN, hypokalemia, metabolic alkalosis, decreased aldosterone

Answer 26

Liddle Syndrome

Question 27

Tx of Liddle Syndrome

Answer 27

Amiloride