AEMCA Practice Exam

What are the receptors associated with the parasympathetic nervous system?

1. Beta 1 and beta 2 receptors

2. Alpha 1 and alpha 2 receptors

3. Muscarinic and nicotinic cholinergic receptors

4. Only alpha receptors

The correct answer is: Muscarinic and nicotinic cholinergic receptors

The correct choice highlights that the receptors associated with the parasympathetic nervous system are muscarinic and nicotinic cholinergic receptors, which are integral to the functioning of this part of the autonomic nervous system. The parasympathetic nervous system primarily uses the neurotransmitter acetylcholine, which binds to these cholinergic receptors. Muscarinic receptors are found on the target organs and are responsible for mediating various parasympathetic effects, such as slowing the heart rate, increasing glandular secretions, and facilitating digestion. On the other hand, nicotinic receptors are located at the neuromuscular junction and in the central nervous system, helping to transmit signals from preganglionic to postganglionic neurons. In contrast, other receptor types listed in the other options, like beta and alpha receptors, are associated with the sympathetic nervous system and are primarily involved in stress-related responses such as increased heart rate and blood pressure. Thus, while they play crucial roles in the body's response to stimuli, they do not represent the primary receptors of the parasympathetic nervous system.