Synaptic Transmission

This post will be dealing with the transmission of impulses across a synapse. 

Chemical Synaptic Transmission

In order for a nerve impulse to travel from one neuron to another the impulse must travel across the synapse. This is done through the release of a neurotransmitter. There are several steps which occur in order for this to happen.

1. AP in the terminal causes voltage gated calcium channels to open.
2. Calcium entry triggers exocytosis of synaptic vesicles. 
3. The transmitter released during exocytosis binds to post synaptic receptors, producing a post synatic response. 

The Release of a Neurotransmitter Across a Synapse

 Post Synaptic Receptors

There are two types of post synaptic receptors:

1. Ionotropic Receptors: They are ligand gated ion channels which produce faster post synaptic responses. The binding of a neurotransmitter causes them to open and this allows ions to move across the membrane of the post synaptic cell, leading to the formation of a graded potential.
2. Metabotropic receptors: The neurotransmitter binds to the receptor which is coupled to a G-protein. The G-protein controls ion channels directly or indirectly through intracellular messengers. This also leads to the formation of a graded potential.  

And that's all folks :). If you have any questions please feel free to ask.