Neurotransmitters

• Neurotransmitters


  Neurotransmitters are chemicals that diffuse across the synapse to the next neuron in the chain. Once the neurotransmitter crosses the gap, it is taken up by the postsynaptic receptor site (the dendrites of the next neuron). Here, the chemical message is converted back into an electrical impulse, and the process of transmission begins again in this other neuron.
• Several dozen types of neurotransmitters have been identified in the brain (as well as in the spinal cord and some glands). Each neurotransmitter has its own specific molecular structure that fits perfectly into a post-synaptic receptor site, similar to a lock and key. Neurotransmitters also have specialist functions; for instance, acetylcholine (Ach) is found at each point where a motor neuron meets a muscle and, upon its release, it will cause muscles to contract.