Chapter 16.5

Question 1

What neurotransmitter is released by all parasympathetic neurons?

Answer 1

The neurotransmitter acetylcholine (ACh) is released by all parasympathetic neurons.

Question 2

Two types of cholinergic receptors occur on the postsynaptic membranes

Answer 2

nicotinic and muscarinic.

Question 3

Describe nicotinic receptors

Answer 3

occur on ganglion cells of both the parasympathetic and sympathetic divisions. When ACh activates nicotinic receptors, it opens chemically gated Na+ channels in the postsynaptic membrane of the ganglionic neuron or motor end plate of the muscle fiber, which always causes excitation of that cell.

Question 4

Describe the muscarinic receptor

Answer 4

occur at cholinergic neuromuscular or neuroglandular junctions The response can be excitatory or inhibitory, depending on the activation or inactivation of specific enzyme

Question 5

How would the stimulation of muscarinic receptors in cardiac muscle affect the heart?

Answer 5

Stimulation of muscarinic receptors, a type of cholinergic receptor located in postganglionic synapses of the parasympathetic nervous system, would cause K+ channels to open, resulting in hyperpolarization of cardiac plasma membranes and a decreased heart rate.