DIT Renal 2. Nephron and Diuretics

Question 1

What class of drugs inhibit the Na+/2Cl-/K+ symporter in the thick ascending limb?

Answer 1

Loop diuretics

Question 2

What determines how much water is reabsorbed in the distal tubules and the collecting ducts?

Answer 2

ADH

Question 3

What two types of cells compose the collecting duct and the last segment of the distal tubule? What do they do?

Answer 3

Principal cells:

1. reabsorb H2O and Na+
2. secrete K+

Intercalated cells:

1. secrete H+ or HCO3-
2. reabsorb K+

Question 4

What are the two types of intercalated cells?

Answer 4

alpha cells - H+ secreting cells

beta cells - HCO3- secreting cells

Question 6

What affect does aldosterone have on the intercalated cells and principal cells of the collecting duct?

Answer 6

Intercalated cells - stimulates acid secretion

Principal cells - increase Na+ reabsorption and K+ secretion

Question 7

What drug antagonizes aldosterone’s action on the principal cells of the collecting duct, thereby promoting Na+ excretion and inhibiting K+ excretion?

Answer 7

Spironolactone

Eplerenone

Question 8

What are the critical steps involved in excreting dilute urine?

Answer 8

1. Dilution of fluid in the TAL as solute is reabsorbed and water remains in lumen (d/t impermeability of H2O in TAL)
2. Absence of ADH –> distal tubule and cortical collecting duct impermeable to H2O
3. Tubular fluid is diluted even more as solute is removed from tubular fluid in distal tubule and cortical collecting duct but water remains
4. B/C of low fluid osmolality in collecting duct and slight permeability of medullary collecting duct to urea, urea enters the tubule from the medullary interstitium thereby keeping the osmolality of the medial interstitium low

Question 13

What class of diuretics directly affects principal cells?

Answer 13

K+ sparing diuretics

Question 28

reabsorbs 67% of the fluid and electrolytes filtered by the glomerulus

Answer 28

proximal tubule

Question 31

segment responsible for concentrating urine

Answer 31

collecting duct

Question 34

glaucoma

Answer 34

mannitol

acetazolamide

Question 35

site of secretion of organic anions and cations

Answer 35

proximal tubule

Question 38

always impermeable to water

Answer 38

thick ascending limb

Question 41

permeable to water only in the presence of ADH

Answer 41

late distal tubule and collecting ducts

Question 44

site of the Na+/2Cl-/K+ co transporter

Answer 44

thick ascending limb

Question 47

site of isotonic fluid reabsorption

Answer 47

proximal tubule

Question 50

site responsible for diluting urine

Answer 50

thick ascending limb

Question 53

only site where glucose and amino acids are reabsorbed

Answer 53

proximal tubule

Question 56

water reabsorption in the loop of henle

Answer 56

thin descending limb

Question 59

Triamterene

Answer 59

K+ sparing

Question 62

Acetazolamide

Answer 62

carbonic anhydrase inhibitor

Question 65

Hydrochlorothiazide

Answer 65

thiazide diuretic

Question 68

Bumetanide

Answer 68

loop

Question 71

Spironolactone

Answer 71

K+ sparing diuretic (aldosterone antagonist)

Question 74

Chlorothiazide

Answer 74

thiazide

Question 77

Ethacrynic acid

Answer 77

loop (not a sulfa drug)

Question 80

Mannitol

Answer 80

osmotic diuretic

Question 83

Metolazone

Answer 83

thiazide diuretic

Question 86

Chlorthalidone

Answer 86

thiazide diuretic

Question 89

Furosemide

Answer 89

loop diuretic

Question 92

Amiloride

Answer 92

K+ sparing diuretic

Question 95

Torsemide

Answer 95

loop diuretic

Question 98

acute pulmonary edema

Answer 98

loops

Question 101

idiopathic hypercalciuria (–>calcium stones)

Answer 101

thiazide diuretics

Question 107

mild to moderate CHF with expanded ECV

Answer 107

loops (maybe thiazide if mild)

Question 110

in conjunction with loops or thiazides to retain K+

Answer 110

K+ sparing diuretics

Question 113

edema associated with nephrotic syndrome

Answer 113

loop diuretic

Question 116

increased intracranial pressure

Answer 116

mannitol

Question 119

mild to moderate HTN

Answer 119

thiazides

Question 122

hypercalcemia

Answer 122

loops

Question 125

altitude sickness

Answer 125

acetazolamide

Question 128

hyperaldosteronism

Answer 128

Spironolactone

Question 129

What is the site of action of mannitol?

Answer 129

proximal convoluted tubule

Question 130

What is the site of action of the thiazides?

Answer 130

distal convoluted tubule

Question 131

A pt with heart failure exacerbation needs medical diuresis but has a sulfa allergy. What diuretic can be used?

Answer 131

Ethacrynic acid