Neurons are the actual nerve fibers of the body. They may be either of three types. Efferent Nerves, Interneurons, Afferent Nerves. Afferent nerves are the sensory receptors responsible for detecting stimuli. Stimuli may be extremely hot surface upon your skin. Interneurons transfer the signal toward the efferent neurons. These are the motor nerve fibers responsible for contracting the muscles in your arms to remove your hand from the hot surface.
Neurotransmitters are the chemical messengers secreted by presynaptic nerve fibers. They are secreted into the synaptic cleft, which is the space between the pre synaptic and post synaptic nerve fibers. Depending upon the strength of the stimulus, a certain concentration will be released. They will attach to the receptors of the post synaptic nerve fibers. NT may either be excitatory or inhibitory. You will have to research where they are located. Some NT are acetylcholine, GABA.
