5) Control of Potassium

Approximately what percentage of filtered potassium (K⁺) is reabsorbed in the proximal convoluted tubule of the nephron?

65%

Approximately what percentage of filtered potassium (K⁺) is reabsorbed in the thick ascending limb of the loop of Henle?

25%

What is the primary effect of aldosterone on potassium handling in the nephron?

It increases potassium secretion in the collecting duct

Where is potassium secreted in the nephron?

Late distal tubule and collecting duct

What hormone increases potassium secretion in the kidney?

Aldosterone

Which of the following drugs increases potassium loss by enhancing sodium delivery to the distal nephron?

Furosemide

Why does furosemide increase potassium excretion?

It enhances sodium and fluid flow through the nephron, increasing potassium secretion

Which of the following scenarios would most likely lead to hypokalaemia?

Vomiting and diarrhoea

Why can vomiting and diarrhoea worsen potassium loss?

They increase aldosterone secretion

How does insulin contribute to hypokalaemia?

Drives potassium into cells

Which of the following conditions is most associated with increased aldosterone levels and potassium loss?

Primary hyperaldosteronism

Which of the following is a common medication class that causes hypokalaemia?

Loop diuretics

What is one of the reasons hypokalaemia may worsen in a patient on steroids?

Steroids stimulate aldosterone production