biochem dwuggy1

Question 1

natriuresis

Answer 1

excretion of sodium in urine via action of kidneys
(decreases Na+ conc. in blood)

Question 2

acid-base balance in kidney

Answer 2

kidneys excrete acidic or alkaline urine (depending on body’s need)

Question 3

when is formation of acidic urine required

Answer 3

to compensate for body’s tendency to decrease body pH due to metabolic production of CO2 (glycolysis)

Question 4

how is k+ balance in kidney critical

Answer 4

even small changes in extracellular k+ concentrations affects the function of excitable cells

Question 5

how does excretion of organic ions work and where is energy derived from

Answer 5

involves active transport
(energy from action of Na+/K+ATPase on basolateral membrane)

Question 6

how do diuretics work on kidneys

Answer 6

increase volume of urine produced by promoting exretion of Na+, Cl-, HCO3 and water from kidneys

Question 7

net result of diuretics on kidney

Answer 7

increased urine flow, altered pH and altered ionic composition of blood and urine

Question 8

what are diuretics used for treating

Answer 8

oedema & hypertension

Question 9

site and mechanism of action for diuretics

Answer 9

osmotic diuretics
carbonic anhydrase inhibitors
loop diuretic
thiazide
k+ sparing diuretics

Question 10

osmotic diuretic (mannitol)

Answer 10

na ions taken up into tubule cell, water can’t flow in usual amount, less na+ conc, less na+ reabsorp,

blood volume decreased
large volume of dilute urine produced

Question 11

what should osmotic pressure be when your body does nor need to conserve water

Answer 11

lumen = cell = interstitium

Question 12

osmotic diuretic indications (mannitol)

Answer 12

promotes:

• diuresis, especially in the prevention of acute renal failure from, eg, increased pigment load due to transfusion reaction
• excretion of toxic substances.

Question 13

osmotic diuretic indications (isosorbide, urea, glycerin mannitol)

Answer 13

reduce intraocular pressure

Question 14

osmotic diuretic indications (urea and mannitol)

Answer 14

approved to reduce intracranial pressure and cerebral oedema

Question 15

why is mannitol preferred over other osmotic diuretic agents

Answer 15

inherently non-toxic
freely filtered
non-reabsorbable
not metabolised
other agents may pass into cells to a limited extent

Question 16

adverse effects of osmotic diuretics

Answer 16

cv toxicity immediately after injection, osmotic action of compounds in vasculature cause osmosis of non-vascular fluids into the vessel, increasing blood volume

increases te workload of heart (increased afterload, peripheral resistance) which may be detrimental.

contraindicated in patients with congestive heart failure.

Question 17

carbonic anhydrase inhibitors (ca-i)

Answer 17

cai prevents formation and subsequent ionisation of h2co3-

Question 18

indications of carbonic anhydrase inhibitors

Answer 18

raised intra-ocular pressure in open-angle glaucoma
ocular hypertension when monotherapy inadequate

Question 19

side effects of carbonic anhydrase

Answer 19

metabolic acidosis
renal stones (calcium and phosphate)
renal potassium wasting (enhanced k+ secretion due to nahco3)

Question 20

side effects of carbonic anhydrase

Answer 20

metabolic acidosis
renal stones (calcium and phosphate)
renal potassium wasting (enhanced k+ secretion due to nahco3)