Afferent (receives information through sensory receptors) and Efferent (takes information from CNS to ie. a muscle) parts. Within the Efferent system you have Somatic actions (voluntary movements) and Autonomic actions (Reflexes that happen that are not voluntary) AND within the Autonomic actions you have Sympathetic (Preparing the body) and Parasympathetic ( inhibits response and calms body back down). With respects to the structure you have 3 main parts: 1. The Cell body (Soma) 2. The Axon and the 3.Axon terminals. The Cell body contains the Cell nucleus, and the Dendrites that receives information from other cells. The Axon itself is covered by Myelin Sheaths (which improves conductivity) and the cover the axon in like separated square bodies. The spaces between these bodies are called "the nodes of Ranvier", and inside these sheaths there are "Schwann Cells". And finally the Axon terminals carry information away from the cell to synapses where it is received by other cell's dendrite. See this pic to see how it all comes together: http://www.daviddarling.info/images/neur\\...