Renal pharmacology

Question 1

Pharmacological site of action of diuretics

Answer 1

nephron

Question 2

How does oedema occur?

Answer 2

imbalance in rate of interstital fluid formation & recapsulation of fluid into capillary circulation

Question 3

Which force drives water out of capillary?

Answer 3

Capillary pressure

Question 4

Which force drives water bac into the capillary?

Answer 4

Capillary oncotic pressur

Question 5

What is capillary oncotic pressure drived from?

Answer 5

Plasma proteins (mainly albumin)
- change in this causes oedema

Question 6

Why are interstitial fluid forces & oncotic forces not really considered in oedema>

Answer 6

value of 0

Question 7

What do conditions that increased capillary pressure and decrease capillary oncotic pressure cause?

Answer 7

Oedema

Question 8

Conditions that cause oedema?

Answer 8

Nephrotic syndrome
Congestive Heart Failure
Hepatic cirrhosis with ascites (resistance to blood flow back to liver, pressure build up in circulation)

Question 9

What is the noral glomerulus impermeable to?

Answer 9

Large plasma proteins

Question 10

What is nephortic syndrome?

Answer 10

Disruption of filtration at glomerulus - large roteins (mainly albumin) enters primary filtrate

Question 11

Landmark clinical finding in nephrotic syndrome

Answer 11

Proteinuria

Question 12

In what situation is proteinuria normal?

Answer 12

Extreme physical exercise

Question 13

What normally causes frothy urine?

Answer 13

Protein

Question 14

Why does nephrotic syndrome cause oedema?

Answer 14

Loss of plasma proteins from blood
Decrease in oncotic pressure
Tendency for oedema formation

Question 15

How does initial decrease in oncotic pressure lead to a further decrease in oncotic pressure?

Answer 15

Decreased oncotic pressure
Increased formation of interstitial fluid
Decrease blood volume - decrease cardiac output
Activation of RAAS
Na+ and H20 retention
FURTHER DECREASE IN ONCOTIC PRESSURE

Question 16

What is congestive heart failure?

Answer 16

Reduced cardiac output which can result from multiple causes

Question 17

Why is the RAAS system activated in congestive heart failure?

Answer 17

Renal hypoperfusion

worsens oedema

Question 18

Fundamental principle of how diuretics work?

Answer 18

Block reabsorbtion of sodium to make us pee out water

Question 19

What condition can half the number of nephrons in your kidneys?

Answer 19

long standing untreated hypertension

Question 20

What is the action of carbonic anhydrase inhibitors?

Answer 20

block Na+/H+ exchange in the proximal convuluted tubule

Question 21

What is the mechanism of action of loop diuretics?

Answer 21

block triple co transporter in the thick ascending loop of Henle (looses its diluting effect) so more sodium is presented to distal part of nephron which can’t cope with increased amount so sodium & chloride are peed out

Question 22

Is the thick ascending Loop of Henle permeable to water?

Answer 22

No

Question 23

Mechanism of thiazide diuretics?

Answer 23

block Na+/Cl- co transporter in distal convuluted tubule

Question 24

Mechanism of acting of potassium sparing diuretics?

Answer 24

block Na+/K+ exchange in collecting tubule

Question 25

Transporters by which diuretics enter filtrate?

Answer 25

Organic anion transporters (OATs)

Organic Cation Transporters (OCTs)

Question 26

Why do diuretics selectively act on the kidney and not other sites?

Answer 26

concentration in filtrate is higher than in blood `