Kidney: Water 4 (diuresis) Flashcards
enumerate types of Diuresis
- Water Diuresis
- Osmotic Diuresis
- Pressure Diuresis
- Drug Diuresis (diuretics)
Cause of Water diuresis
drinking large volume of water or hypotonic fluid
Onset of water diuresis
15-40 mins after drinking
Mechanism of water diuresis
- Decrease plasma osmolarity (due to hypervolemia)
- inhibition of ADH
- No facultative reabsorption of water (at collecting duct)
Result of water diuresis
Excretion of large amounts of Hypotonic urine (with no increase in solute secretion)
Cause of Osmotic Diuresis
presence of large amounts of solutes inside renal tubule, such as:
* Glucose in uncontrolled diabetes mellitus
* Mannitol
* Large amounts of urea
Mechanism of osmotic diuresis
- Drop in both Obligatory & facultative water reabsorption
Result of osmotic diuresis
Excresion of large amount of Hypotonic or isotonic urine, with incerease in solute secretion
Diuretic Effect of Carbonic Anhydrase inhibitor (acetozolamide or diamox)
- Decrease Hydrogen secretion
- Increase Na+, bicarb, water and potassium secretion
Diuretic Effect of Loop duretic (lasix= furosemide)
- inhibits sodium-potassium-chloride Co transporter at thick part of Ascending loop of henle
- therefore increase elctrolyte Excretion
Diuretic Effect of Thiazide Diuretic
inhibts NaCl reabsorption by early DCT
Diuretic Effect of Aldosterone inhibitor (Aldactone)
inhibits Na+ K+ exchanger
* increase Na+ excretion
* increase K+ Retention (decrease excretion)
Diuretic Effect of Xanthine (caffeine)
- increases GFR
- so Decreases Na+ reabsorption
- leading to osmotic diuresis
Diuretic Effect of Ethanol (alcohol)
Inhibts ADH secretion, prevents water retention, increases Water excretion (diuresis)
