Question

Becca was stung by a bee and minutes later went into anaphylactic shock. Her friend Amal grabbed Becca's EpiPen from her backpack and injected it into Becca's thigh. How did the injection of epinephrine BEST help Becca during anaphylaxis?
A. It caused Becca's immune system to release more chemicals to fight the allergic reaction
B. It forced Becca's body into a fight-or-flight response and stopped the allergic reaction
C. It slowed Becca's blood flow so the allergens stopped moving throughout the body
D. It caused Becca's respiratory rate to increase so she could get enough oxygen

Answer 1

Answer: B.

Explanation: Epinephrine activates the sympathetic "fight-or-flight" response (alpha and beta adrenergic receptors). Alpha-1 vasoconstriction raises blood pressure and reduces airway/skin swelling; beta-2 causes bronchodilation and reduces mediator release from mast cells; beta-1 increases cardiac output. These effects rapidly reverse the hypotension, airway swelling and bronchospasm of anaphylaxis.

Why the others are wrong:
- A is wrong — epinephrine does not increase immune chemical release; it helps stop mediator release.
- C is misleading — epinephrine causes vasoconstriction but not by “slowing blood flow” to trap allergens.
- D is wrong — epinephrine improves airflow by bronchodilation, not primarily by increasing respiratory rate.