Question

In addition to neurons, muscle cells undergo depolarization, although smaller and slower than in the neuron, as a result of the activity of the acetylcholine receptor.

(a) The acetylcholine receptor is also a gated ion channel. What triggers the gate to open?
(b) The acetylcholine receptor/ion channel is specific for $\mathit{N}{\mathit{a}}^{\mathbf{+}}$ions. Would ions flow in or out? Why?

(c) How would the $\mathit{N}{\mathit{a}}^{\mathbf{+}}$flow through the ion channel change the membrane potential?

Short answer

(a) It triggers the acetylcholine in an open state.

(b) The ${\text{Na}}^{\text{+}}$ions flow into the muscle cells by acetylcholine receptor.

(c) The influx of the positive charge increases the membrane potential by opening of the additional ion channels.

Step-by-step solution

Acetylcholine

When electrical impulses travel along a motor neuron, a neurotransmitter known as acetylcholine is released from the nerve cell's terminal. Acetylcholine, a physiologically active chemical, works by attaching to and activating receptors on the cell surface

In solution (a), Triggering of acetylcholine receptor

A ligand-gated ion channel that is permeable topotassium, sodium, and calcium ions, the nicotinic acetylcholine receptor is one kind ofcholinergic receptor. The channel opens when acetylcholine binds to a ligand-gated transporter. When acetylcholine attaches to these ion channels implanted in the cell membrane, they change from closed to open, allowing ions to flow through.

In solution (b), Na+ ions flows in or out

Ligands attach to the receptor in the cell, and theion channel component of the receptor unlocks, allowing ions to flow through the membrane. The membrane potential provides a significant inwardelectrochemical driving forceas well as a big store of ions.Acetylcholine receptorsopen the cell membrane, allowing ions from the ions to enter.

In solution (c), Na+ flows through the membrane channel

Depolarization happens when ${\text{Na}}^{\text{+}}$passes through the ion channel. Depolarization opens channels in the membrane, allowing a little quantity of ${\text{Na}}^{\text{+}}$to flow into the cell down to its electrochemical gradient. The input of positive charge raises the membrane potential by allowing more ion channels to open.

As a result, acetylcholine is triggered in an open state. Acetylcholine receptors allow ions to pass into muscle cells. By activating new ion channels, the input of positive charge raises the membrane potential.