A neural network

The brain controls body action through electrical stimulus of a vast network of neural connections.  These electrical stimuli, known as action potentials, travel through bundles of nerve cells known as neurons.  Neurons are specially structured cells that allow impulses from the brain to travel great distances in extremely short periods of time.  Neurons consist of a cell body, or soma, and a specialized fiber-like projection known as an axon.  The axon is insulated by a structure known as the myelin sheath that consists of specialized Schwann cells.  Electrical stimuli are received at the soma through extensions called dendrites, and are quickly passed on through the myelinated axon to another nerve cell, which in turn receives the signal through its dendrites and passes the signal on to its axon.  This is how action potentials propagate through the nervous system.

Figure 2:  Cellular anatomy of the nervous system