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
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
