Cardiovascular pharmacology V

Question 1

where is potassium primarily reabsorbed?

Answer 1

proximal convoluted tubule

Question 2

what is reabsorbed at the proximal convoluted tubule?

Answer 2

1. bicarb
2. sodium (and water)
3. potassium
4. glucose
5. amino acids

Question 3

what is reabsorbed at the thin descending limb?

Answer 3

water

Question 4

what is the main transporter of the thick ascending limb?

Answer 4

Na/K/2Cl

Question 5

what is the main transporter of the distal convoluted tubule?

Answer 5

Na-Cl

Question 6

reabsorption of what molecules takes place in the collecting duct?

Answer 6

1. sodium
2. water

at the effect of aldosterone

Question 7

where does aldosterone exert its effects?

Answer 7

collecting duct (sodium and water reabsorption)

Question 8

where does ADH exert its effects?

Answer 8

collecting duct - blocking water reabsorption

Question 9

what is the result of increased tubular solute concentration?

Answer 9

secretion of potassium at the collecting duct (loss of potassium - can cause arrhythmias)

Question 10

what are the three main mechanisms of action of the carbonic anhydrase inhibitors?

Answer 10

1. decrease reabsorption of bicarb in PCT (main)
2. increase in U-HCO3 excretion
3. loss of bicarb / increase ammonium secretion

Question 11

what is the result of decreasing reabsorption of bicarb in the PCT?

Answer 11

1. increase solute delivery to macula densa
2. TGF - tubular glomerular feedback
3. increase afferent arteriole resistance
4. decrease in renal blood flow and GFR

Question 12

what is the result of increasing U-HCO3 excretion?

Answer 12

1. increased NaCl excretion
2. diuresis, increased potassium excretion
3. increased urine pH and metabolic acidosis

Question 13

what is the result of losing bicarb and increaseing ammonium secretion?

Answer 13

1. increased urine pH

2. metabolic acidosis

Question 14

what class of drug is acetazolamide?

Answer 14

carbonic anhydrase inhibitor

Question 15

what are the clinical applications of acetazolamide?

Answer 15

1. glaucoma
2. acute mountain sickness
3. induce urinary alkalinization
4. edema

Question 16

what are the contraindications of acetazolamide use?

Answer 16

cirrhosis

Question 17

what is the mechanism of action of osmotic diuretics?

Answer 17

1. freely filtered but poorly reabsorbed
2. increase tubular fluid osmotic pressure - decrease tubular fluid reabsorption
3. stimulation of potassium secretion (risk of hypokalemia)

Question 18

what is the main site of action for osmotic diuretics?

Answer 18

thin limbs of the loop of Henle

Question 19

what is the main osmotic diuretic agent?

Answer 19

mannitol

Question 20

what are the clinical applications of osmotic diuretics?

Answer 20

1. prophylaxis of acute renal failure
2. cerebral edema
3. dialysis disequilibrium syndrome
4. acute attacks of glaucoma

Question 21

how do osmotic diuretics prevent acute renal failure?

Answer 21

1. expand ECV
2. maintain GFR
3. increase tubular fluid flow
4. prevent tubule obstruction from shed cell constituents or crystals
5. reduce renal edema

Question 22

what are the adverse effects of osmotic diuretics?

Answer 22

extracellular volume expansion

Question 23

loop diuretics act on what transporter? where?

Answer 23

1. Na-K-2Cl pump

2. thick ascending limb

Question 24

furosemide is what type of diuretic?

Answer 24

loop

Question 25

what is the main effect of loop diuretics?

Answer 25

venodilation - decrease right atrial pressure and pulmonary capillary wedge pressure within minutes

Question 26

what is the mechanism of action for loop diuretics?

Answer 26

1. increase fractional calcium excretion by 30% by decreasing lumen-positive transepithelial potential that promotes paracellular calcium reabsorption 2. increase fractional magnesium excretion more than 60% by decreasing voltage-dependent paracellular transport 3. an alternative way to decrease plasma calcium

Question 27

what are the clinical applications of loop diuretics?

Answer 27

1. pulmonary edema 2. CHF 3. acute renal failure 4. hyperkalemia - saline and loop diuretics

Question 28

what are the major adverse effects of loop diuretics?

Answer 28

1. HYPOKALEMIA 2. hyponatremia 3. hypocalcemia 4. hypomagnesia 5. ototoxicity 6. hyperuricemia