Diuretics summary

Diuretics
The Nephron




What happens in the glomerulus?
 Glomerulus is a network of tiny blood vessels.
 Filters the blood under pressure.
 Into the Bowman’s capsule’s filtrate.
 This includes water and small molecules.

What happens in the loop of Henle?
Thick ascending loop: impermeable to water, actively transports sodium out of the filtrate
into the blood and potassium into the filtrate.
By reabsorbing salts this reabsorbs water by osmosis.
Thin descending loop: water reabsorbed, permeable to water.
Decreasing the amount of water and sodium in the filtrate.

What happens in the distal convoluted tubule?
Impermeable to water
Na+/K+ pump to further reabsorb sodium into the vessel.
And excrete potassium.
Aldosterone enhances reabsorption by opening sodium ion channels.
Increasing the activity of the sodium-potassium pumps.

Loop Diuretics
Mechanism Of Action
 Inhibits Na+/K+/2Cl- cotransporter.
 Binding to the chloride binding site
 In the ascending loop of Henle
 Preventing sodium reabsorption
 So, water isn’t reabsorbed by osmosis.
 Vasodilation effects: to balance the loss of water and decreased fluid, nitric oxide
and prostaglandins are secreted to relax the blood vessels. Causing vasodilation.
 Most effective diuretic
Indications
 Chronic heart failure with fluid retention
 Pulmonary and peripheral oedema