Question

Describe, in order, the events that occur to transmit an electrical signal from a presynaptic neuron to either a postsynaptic neuron or a muscle cell.

Answer 1

1. Transmitter is synthesized and stored in a testicle
2. An action potential comes down the presynaptic cell and causes depolarization - activates it, nerve impulse reaches the axon terminal causing depolarization of the synaptic knob
3. Voltage sensitive Ca2+ channels open and causes an influx of calcium (tells the testicles to exocytose)
4. Vesicles fuse with the pre synaptic neuronal membrane
5. Synaptic vesicles are released via exocytosis in the synaptic cleft
6. neurotransmitter diffuses across the synaptic cleft and binds to cell surface receptor proteins on post synaptic membrane
7. Causes the opening or closing of post synaptic channel and can cause a depolarization
8. An action potential can be triggered in post synaptic cell (if threshold was crossed) excitatory leads to depol and inhibitory is less likely to depol.
9. Retrieval of Vescial membrane from plasma membrane