Medical Laboratory Scientist (MLS) ASCP Practice Exam

Which of the following is NOT a function of angiotensin II?

1. Increased vasodilation

2. Increased blood volume

3. Stimulation of aldosterone secretion

4. Increased blood pressure

The correct answer is: Increased vasodilation

Angiotensin II plays a crucial role in the body's regulation of blood pressure and fluid balance. One of its primary functions is to induce vasoconstriction, which is a narrowing of blood vessels. This action leads to increased blood pressure, making angiotensin II a potent vasopressor. Increased blood volume is another function associated with angiotensin II, particularly through the stimulation of the secretion of aldosterone from the adrenal glands. Aldosterone promotes sodium and water reabsorption in the kidneys, which raises blood volume and subsequently blood pressure. Additionally, angiotensin II directly contributes to increased blood pressure not only through vasoconstriction but also by promoting thirst and encouraging fluid intake, further enhancing blood volume. In contrast, increased vasodilation is not a function of angiotensin II. Vasodilation refers to the widening of blood vessels, which would effectively decrease blood pressure rather than increase it. Therefore, identifying that increased vasodilation is not a function of angiotensin II reflects an understanding of its physiological role in the renin-angiotensin-aldosterone system (RAAS) and its impact on cardiovascular regulation.