A review of the nervous system involving:the composition of a nerve, the anatomy of the neuron, the physiology of the nerve impulse, the synapse, neurotransmitters, the response by muscles and/or glands. Agonist and antagonist drug response as well as esterase activity within the synaptic gap and the differences in response caused by different receptor types was discussed. This will now lead into the effects of different drug categories on the nervous system, starting with anesthesia.