AEMCA Practice Exam

Which receptors are part of the sympathetic nervous system?

1. Muscarinic and nicotinic receptors

2. Alpha 1 and alpha 2 receptors

3. Beta 1, beta 2, alpha 1, and alpha 2 receptors

4. Cholinergic receptors only

The correct answer is: Beta 1, beta 2, alpha 1, and alpha 2 receptors

The sympathetic nervous system primarily utilizes adrenergic receptors, which play vital roles in mediating the body's response to stress and emergencies, often referred to as the "fight or flight" response. The correct choice encompasses both the alpha and beta subtypes of adrenergic receptors. Beta 1 receptors are largely involved in increasing heart rate and contractility, contributing to enhanced cardiac output. Beta 2 receptors facilitate the dilation of bronchial passages, leading to improved airflow, and they also promote vasodilation in certain blood vessels. Alpha 1 receptors generally cause vasoconstriction, enhancing blood pressure, while alpha 2 receptors primarily function in feedback inhibition to modulate neurotransmitter release. Thus, the inclusion of all four receptor types—beta 1, beta 2, alpha 1, and alpha 2—captures the complete functional role of the sympathetic nervous system in autonomic regulation and cardiovascular responses. This makes the option encompassing these receptors the most comprehensive and accurate representation of the receptors involved in the sympathetic nervous system.