During an allergic reaction, which of the following would aid respiration?

• A. Insulin
• B. Epinephrine
• C. Acetylcholine
• D. Histamine

Answer: (B)

Verified step by step guidance

1. Understand the context of the problem: An allergic reaction can cause symptoms such as difficulty breathing due to airway constriction or inflammation. The goal is to identify which substance aids respiration during such a reaction.
2. Review the role of each substance listed: Insulin regulates blood sugar levels and is unrelated to respiration or allergic reactions. Acetylcholine is a neurotransmitter that can cause bronchoconstriction, which would worsen breathing difficulties. Histamine is released during allergic reactions and contributes to inflammation and airway constriction, making breathing harder.
3. Focus on epinephrine: Epinephrine, also known as adrenaline, is a hormone that can counteract the effects of an allergic reaction. It works by relaxing the smooth muscles in the airways, reducing inflammation, and improving airflow.
4. Understand the mechanism of epinephrine: Epinephrine binds to beta-adrenergic receptors in the lungs, leading to bronchodilation (widening of the airways). This helps alleviate breathing difficulties during an allergic reaction.
5. Conclude that epinephrine is the correct answer because it directly aids respiration by reversing airway constriction and inflammation caused by the allergic reaction.