AEMCA Practice Exam

Which hormone is primarily involved in renal factors of blood pressure control?

1. Cortisol

2. Aldosterone

3. Adrenaline

4. Thyroxine

The correct answer is: Aldosterone

Aldosterone is primarily involved in the renal factors of blood pressure control due to its significant role in regulating sodium and potassium levels in the kidneys. It is a steroid hormone produced by the adrenal glands, and its primary function is to promote the reabsorption of sodium ions from the urine back into the blood. As sodium is reabsorbed, water follows osmotically, which increases blood volume and consequently raises blood pressure. Aldosterone also facilitates the excretion of potassium, helping to maintain electrolyte balance. This mechanism makes aldosterone critical in the body's response to changes in blood pressure and fluid balance. When blood pressure drops, the body releases renin, which activates the renin-angiotensin-aldosterone system (RAAS); aldosterone is then secreted to help restore blood pressure to normal levels. Other hormones listed, such as cortisol, adrenaline, and thyroxine, have various roles in metabolism and stress response but are not primarily focused on regulating blood pressure through renal function.