The nurse is explaining to a patient how ACE inhibitors affect blood pressure. Which statement accurately describes the action of these medications?
A.
They lower heart rate.
B.
They inhibit vasoconstriction.
C.
They increase aldosterone secretion.
D.
They promote sodium retention.
The correct answer and Explanation is :
The correct answer is B. They inhibit vasoconstriction.
Explanation:
ACE inhibitors, or Angiotensin-Converting Enzyme (ACE) inhibitors, are a class of medications used to treat high blood pressure (hypertension), heart failure, and other cardiovascular conditions. To understand how ACE inhibitors work, it’s important to first recognize the role of the Renin-Angiotensin-Aldosterone System (RAAS) in regulating blood pressure.
- RAAS Pathway:
- When blood pressure drops, the kidneys release a hormone called renin.
- Renin converts angiotensinogen (produced by the liver) into angiotensin I.
- Angiotensin I is then converted into angiotensin II by the angiotensin-converting enzyme (ACE), which is found mainly in the lungs.
- Angiotensin II has two key effects: it causes vasoconstriction (narrowing of the blood vessels), which increases blood pressure, and stimulates the release of aldosterone, a hormone that promotes sodium and water retention by the kidneys, further increasing blood volume and blood pressure.
- Mechanism of ACE Inhibitors:
ACE inhibitors block the enzyme ACE, which prevents the conversion of angiotensin I to angiotensin II. As a result, the effects of angiotensin II—vasoconstriction and aldosterone secretion—are reduced. - Vasoconstriction Inhibition:
Since angiotensin II is a potent vasoconstrictor, inhibiting its production leads to vasodilation (widening of the blood vessels). This vasodilation reduces resistance in the blood vessels, lowering blood pressure. - Impact on Blood Pressure:
By preventing vasoconstriction and reducing sodium and water retention, ACE inhibitors lower overall blood pressure. They are commonly prescribed for patients with hypertension, heart failure, and kidney disease.
Thus, ACE inhibitors inhibit vasoconstriction, making B the correct answer.