What results from the activation of the renin-angiotensin-aldosterone system during hemorrhage?

The activation of the renin-angiotensin-aldosterone system (RAAS) during hemorrhage plays a crucial role in the body's response to maintain blood pressure and blood volume. In the event of hemorrhage, blood volume decreases, leading to a drop in blood pressure. This drop in blood pressure is detected by baroreceptors, which signal the kidneys to release the enzyme renin.

Renin catalyzes the conversion of angiotensinogen, produced by the liver, into angiotensin I. Angiotensin I is then converted to angiotensin II by the action of angiotensin-converting enzyme (ACE), primarily in the lungs. Angiotensin II has several important effects: it causes vasoconstriction, which increases systemic vascular resistance and thus raises blood pressure. Importantly, angiotensin II also stimulates the adrenal cortex to release aldosterone. Aldosterone enhances sodium (Na+) reabsorption in the renal tubules of the kidneys.

This sodium resorption leads to an increase in water retention, as water follows sodium osmotically. This helps to increase blood volume and blood pressure, counteracting the effects of hemorrhage. Therefore, the correct answer indicates that during hemorrhage, the activation of the