Regarding the parasympathetic pathway... Which neurotransmitter is released by preganglionic neurons? Which neurotransmitter is released by postganglionic neurons? To what types of receptors do these neurotransmitters bind? What is the effect of the neurotransmitter on the target cells? Choose the appropriate key terms from the following list: ACh, NE, nicotinic, muscarinic, alpha-1, alpha-2, beta-1, beta-2, excitatory, inhibitory.

Answer 1

In the parasympathetic pathway:

1. Preganglionic neurons release the neurotransmitter ACh (acetylcholine).
2. Postganglionic neurons also release ACh (acetylcholine).
3. The neurotransmitter released by preganglionic neurons (ACh) binds to nicotinic receptors on postganglionic neurons. The ACh released by postganglionic neurons binds to muscarinic receptors on target cells.
4. The effect of ACh on the target cells varies but is generally considered excitatory for smooth muscles and inhibitory for cardiac muscles.

Thus, the complete answer is:

• Preganglionic neurotransmitter: ACh
• Postganglionic neurotransmitter: ACh
• Receptor for preganglionic ACh: nicotinic
• Receptor for postganglionic ACh: muscarinic
• Effect on target cells: Generally excitatory (smooth muscle) or inhibitory (cardiac muscle).