Which segment of the nephron does aldosterone primarily affect?

Aldosterone primarily affects the late distal convoluted tubule and the collecting duct of the nephron. It is a steroid hormone produced by the adrenal cortex and plays a crucial role in the regulation of sodium and potassium balance in the body.

In the late distal convoluted tubule and the collecting duct, aldosterone promotes the reabsorption of sodium ions from the tubular fluid back into the blood. This process occurs through the action of epithelial sodium channels (ENaC) and increases the activity of the sodium-potassium ATPase pumps on the basolateral membrane, which helps to maintain the electrochemical gradient essential for various cellular functions. As sodium is reabsorbed, water follows osmotically, contributing to increased blood volume and blood pressure.

Additionally, aldosterone facilitates the excretion of potassium, which serves to maintain potassium homeostasis and avoid hyperkalemia. The effects of aldosterone are critical for regulating blood pressure and fluid balance in the body, especially during periods of dehydration or low blood volume.

While options such as the early distal convoluted tubule and proximal convoluted tubule are involved in different aspects of renal physiology, they are not the primary sites influenced by aldosterone, which specifically acts on the late distal convoluted tub