B3 Diuretics

Question 1

Functions of Kidney

Answer 1

Reg of water & inorganic ion balance
Removal of metabolic waste from blood & urine
Gluconeogenesis
(ADME: Absorption, Distribution, Metabolism & Excretion)

Question 2

Adrenals - what is controls at each portion

1. Cortex
2. Medulla

Answer 2

1. cortex
Mineralocorticoids (Aldosterone) 
- Na+, K+ & water homeostasis
- Affect on Na channels/ absorption --> roll on effect K 
Zona Fasciculata
- Glucocorticoids (Cortisol)
- Glucose homeostasis and many others
Zona Reticularis
- Sex steroids (androgens)
- E.g. Testosterone 

2. Medulla
   Catecholamines
   e.g. Adrenaline, Noradrenaline, dopamine

Question 3

what contributes to high hydrostatic P

Answer 3

short, wide afferent arteriole (low R to flow) and the long, narrow efferent arteriole (high R).

Question 4

A decrease in glomerular P results in

Answer 4

a drop in P stims sympathetic nerves & anti diuretic hormone release –> both increase blood volume –> increases vasoconstriction, increase vascular peripheral resistance

Question 5

What is long-term blood pressure controlled by

Answer 5

by controlling blood volume

aldosterone results in increased intravascular blood volume (+ Na absorption

Question 6

Give examples of directs & where do they act

1. Loop diuretics
2. Thiazides
3. Potassium sparing diuretics

Answer 6

1. furosemide supplemented with spironolactone or amiloride
   thick segment of ascending limb of loop of Henle
2. Bendroflumethiazide
   early distal tubule
3. Amiloride
   Not acting directly on sodium channels (relatively weak diuretics)
   Late distal convoluted tubule & collecting duct (distal nephron)

Question 7

Mech of action

1. Loop diuretics
2. Thiazides
3. Potassium sparing diuretics

Answer 7

1. inhibit Na+/K+/2Cl−co-transporter in TAL
2. inhibit Na+/K+ transporter in distal tubule
3. AT1R antagonist: blocking maintains Na balance