Synapses and Neurotransmitters

 

Axon

The long projection of the nerve cell which carries the impulse to another part of the body

Synapse

Where the axon ends and the impulse must be passed to another cell

Axon terminus

The tip of the axon. Usually divided into several branches

Synaptic boutons

Swellings at the tip of each axon terminus.

Synaptic gap or synaptic cleft

The space between the axon terminus and the next cell

Presynaptic cell

The nerve cell before the synapse

Postsynaptic cell

The cell after the synapse

Neurotransmitters

Chemical that are released by the synaptic boutons and diffuse across to the postsynaptic cell

Neurotransmitter receptors

These proteins on the membrane of the postsynaptic cell are the only places where neurotransmitters can attach.

Excitatory postsynaptic potential (ESPS)

When a neurotransmitter goes across the synapse and causes the next cell to depolarize or become more positive. If the next cell gets enough ESPSs, it will fire.

Inhibitory postsynaptic potential (ISPS)

When a neurotransmitter goes across the synapse and causes the next cell to hyperpolarize or become more negative. This will make the cell harder to fire.

Acetylcholine (Ach)

The neurotransmitter your nerves use to stimulate your skeletal muscles

Cholinergic receptors

The proteins on your muscle cells that Ach can attach to, to make the muscle cells react

Muscarinic receptors

A kind of Ach receptor that can also be stimulated by the drug muscarine. These receptors cause an inhibitory postsynaptic potential in the heart, making it slow down.

Nicotinic receptors

A kind of Ach receptor that can also be stimulated by the drug nicotine. These receptors cause excitatory postsynaptic potentials in your muscles, allowing you to move.

Acetylcholinesterase (AchE)

An enzyme on the surface of the postsynaptic cell. Its job is to destroy acetylcholine so the stimulus caused by the acetylcholine can stop.