Nerve cells:

In eukaryotes possibly the most rapid and complex signaling is mediated through nerve impulses.  The Nerve  cells  (neurons)  consist of a cell  body  with numerous projections  of  the  plasma  membrane,  known as  dendrites.  These  interact with  other  cells and receive  information  from  them  in  the  form  of  nerve impulses. Cell body then assimilates the information derived from a number of dendritric contacts and passes on the information as another nerve impulse down the huge axon.  The  axon  ends at the synapse where it makes contact with the post-synaptic  (target) cell. The axon is covered  in places through a membranous  myelin  sheath, made up commonly of the lipid sphingomyelin, that acts as an electrical insulator and enabling the nerve impulses to be transmitted over long distances sometimes more than 1 m in larger animals. Each  millimeter  or  so  along  the  axon  the  myelin sheath is interrupted through

figure:   Schematic diagram of a typical nerve cell.

unmyelinated regions known the nodes of Ranvier in the figure. The end of the axon the nerve terminal, is total of synaptic  vesicles which store the chemical neurotransmitters,  like  as  acetylcholine. When a nerve impulse reaches the nerve terminal the synaptic vesicles release their contents into the synaptic cleft, the space  among the pre- synaptic cells and post-. The neurotransmitter then diffuses across interacts and space with receptors on the surface of the post- synaptic cell which is causing a signal to be transduced in that cell.