According to the BBC, the function of nerve cells is to transmit electrical messages and signals throughout the body. There are three types of nerve cells. Sensory neurons collect and transmit information about stimuli, such as sound, light and temperature. Motor neurons transmit electrical impulses from the brain to the rest of the body and are connected to sensory neurons by specialized cells called association neurons.
The human body contains millions of nerve cells that transmit electrical impulses almost instantaneously. All nerve cells have a body and two kinds of fibers extending away from the body. Fibers called dendrites transmit electrical impulses to the cell body, and axon fibers collect the impulses from the body and transmit them toward the next cell in the given neural pathway. The BBC reveals that both types of fibers reach a maximum length of one meter.
Adjacent nerve cells, however, do not touch. When a nerve impulse reaches the terminus of a given nerve cell, it must bridge the tiny gap separating that cell from the next. At this point, the first neuron produces a chemical called a neurotransmitter that spreads out and activates the dendrites of the second cell. This activation produces another electrical impulse, which travels along the cell's axons before the transmission cycle begins anew.