Epinephrine raises blood pressure by causing what?

Epinephrine raises blood pressure by causing what?

• A. Arteriolar vasoconstriction
• B. Vasodilation
• C. Decreased heart rate
• D. Decreased cardiac output

Answer: (A)

Epinephrine raises blood pressure mainly through arteriolar vasoconstriction. It activates alpha-1 receptors on vascular smooth muscle, causing constriction of arterioles and increasing systemic vascular resistance, which raises both systolic and diastolic pressures. It also boosts heart rate and contractility via beta-1 receptors, which can further increase blood pressure by raising cardiac output, while beta-2 effects can cause some vasodilation in certain beds. However, the overall rise in pressure is driven by the vasoconstriction. The other options would lower pressure or fail to explain the primary effect: vasodilation reduces resistance, and decreased heart rate or decreased cardiac output lowers blood pressure.

Epinephrine raises blood pressure mainly through arteriolar vasoconstriction. It activates alpha-1 receptors on vascular smooth muscle, causing constriction of arterioles and increasing systemic vascular resistance, which raises both systolic and diastolic pressures. It also boosts heart rate and contractility via beta-1 receptors, which can further increase blood pressure by raising cardiac output, while beta-2 effects can cause some vasodilation in certain beds. However, the overall rise in pressure is driven by the vasoconstriction. The other options would lower pressure or fail to explain the primary effect: vasodilation reduces resistance, and decreased heart rate or decreased cardiac output lowers blood pressure.