Question

explain the different effects the neurotransmitter acetylcholine has on voluntary skeletal muscle versus cardiac muscle. for each type of muscle, identify the subdivision of the nervous systerm that is releasing acetycholine.

Answer 1

A neurotransmitter like acetylcholine has excitatory and inhibitory effect depending upon the type of receptors.

In skeletal muscle the receptor for acetylcholine is Nicotonic receptors, they are also known as cholinergic receptors since they bind to acetylcholine, when acetylcholine binds to these receptors they cause the depolarization of the target cell, which causes the muscles to contract, thus the neurotransmitter acetylcholine is excitatory at the neuromuscular junction in skeletal muscle.

In cardiac muscle, the receptor for acetylcholine is muscarinic receptors, when acetylcholine binds to these receptors, they cause hyperpolarizatioin of the target cell, which inhibits the firing of an action potential, thus neurotransmitter acetylcholine is inhibitory at the neuromuscular junction in cardiac cells. Inhibitory action of acetylcholine decreases the heart rate and myocardial contraction.

Nicotinic receptors (skeletl muscle) help transmit outgoing signals for the sympathetic and parasympathetic systems.

Muscarinic receptors( cardiac muscles) help transmitting signals only to the parasympathetic system