Read about the Factors that regulate Aldosterone secretion
Read about the ‘ Factors that regulate Aldosterone secretion’ Please READ * Chapter 38 in Ganong * relevant sections in Chapter 14 Chapter 20 Chapter 24 Chapter 39
Diuresis – Markedly increased output of urine volume Diuretics – Substances that increase the rate of urine volume output Most ‘diuretics’ also increase urinary excretion of electrolytes.
Water Diuresis • Water reabsorption in Osmotic Diuresis * Decreased the PCT – normal • Vasopressin secretion - inhibited • Urine osmolality – reduced (Hypotonic urine) * maximum vasopressin secretion * Urine osmolality = plasma osmolality (Isotonic urine)
Types of diuretics & mechanisms of action 1. Water 2. 2. Ethanol secretion - Inhibits vasopressin 3. 3. Antagonists of - Inhibit action of vasopressin on V 2 vasopressin collecting duct 4. receptors
4. Osmotic diuretics - Produce osmotic diuresis eg. Mannitol, urea, sucrose, glucose 5. Xanthines- - Decrease tubular caffeine & reabsorption of Na+ and theophylline increase GFR 6. Carbonic anhydrase - Inhibit H+ secretion inhibitorsacetazolamide
7. Thiazide Diuretics eg. chlorothiazide & metolazone 8. Loop diuretics eg. furosemide, - Inhibit Na+-Clcotransporter in the early distal tubule - Decrease active reabsorption of Na+, Cl- & bumetanide & K+ in the thick ascending ethacrynic acid loop of Henle
9. Competitive inhibitors – Decrease Na+ of aldosterone reabsorption from and eg. Spironolactone K+ secretion into the collecting tubule 10. Na+ channel blockers eg. Amiloride & triamterene - Decrease Na+ reabsorption from the collecting tubule 9 & 10 – K+ sparing natriuretics
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