Neurotransmission

Neurotransmission (latin: transmissio = passage, crossing; from transmitto = send, let through), also called synaptic transmission, is the transfer of signals between neurons.

All experiences, such as thoughts and feelings, and all actions, are the results of neurons generating nerve impulses in their axons. Without nerve impulses an organism is clinically dead, so they are essential for the organisms existence.
Neurons form networks through which nerve impulses travel. Each neuron receives as many as 15.000 connections from other neurons. Neurons don't touch each other, but they have contact points that are called synapses. A neuron transports its information by way of a nerve impulse. A nerve impulse arriving at the synapse, influences the neuron it is connected with, either in an inhibitory way or in an excitatory way. This next neuron is connected to many more neurons, and if the total of excitatory influences is more than the inhibitory influences, it will also "fire", that is, it will create a new action potential at its axon hillock, in this way passing on the information to yet another next neuron, or resulting in an experience or an action.

Stages in neurotransmission at the synapse

Main article: Chemical synapse

1. Synthesis of the neurotransmitter. This can take place in the cell body, in the axon, or in the axon terminal.
2. Storage of the neurotransmitter in storage granules or vesicles in the synapse.
3. Release of the neurotransmitter into the synaptic cleft.
4. After its release, the transmitter acts on a receptor in the postsynaptic membrane.
5. Deactivation of the neurotransmitter. The neurotransmitter is either destroyed, or taken back into the terminal from which it came, where it can be reused, or degraded and removed.