The following are steps involved in transmission at the cholinergic synapse: 1. Chemically gated ion channels on the postsynaptic membrane are opened.
2. Calcium ions enter the axon terminal.
3. An action potential depolarizes the axon terminal at the presynaptic membrane.
4. Acetylcholine is released from storage vesicles by exocytosis.
5. Acetylcholine binds to receptors on the postsynaptic membrane

3. Step 1; An action potential depolarizes the axon terminal at the presynaptic membrane

2. Step 2; Calcium ions enter the axon terminal

4. Step 3; Acetylcholine is released from storage vesicles by exocytosis

5. Step 4; Acetylcholine binds to receptors on the postsynaptic membrane

1. Step 5; Chemically gated ion channels on the postsynaptic membrane are opened

Explanation:

3. The cholinergic synapse starts at the point of arrival of an electrochemical impulse or action potentials at the synaptic knob of the axon terminal of a presynaptic neuron membrane

2. The arrival of the action potential at the axon terminal causes the calcium ion Ca²⁺ channels to open and Ca²⁺ enters into the synaptic knob, resulting in the fusion of the presynaptic membrane and synaptic vesicles

4. The fusion enables the release into the synaptic cleft of many acetylcholine (ACh) transmitter molecules by exocytosis

5. Some of the ACh are transported across the synaptic cleft and bind to postsynaptic neuron membrane embedded ACh receptors

1. The binding of the ACh neurotransmitter molecules to receptors on the membrane of the dendrites of a neuron it leads to the opening of ion channels