The basic unit of the nervous system is the neuron, or nerve cell. Neurons are distinguished from other cells by their ability to communicate with other neurons through synaptic transmission and form highly structured communication networks. Neurons are electrically excitable cells that receive, process and transmit information using electrical and chemical signals.
Neurons are also different from other cells by virtue of their being highly polarized with uniquely specialized and distinct morphological regions. The dendrites are the regions where signals from other neurons are received. The axon is a key part of the cell and transmits signals from one region to another. Synapses are the terminal regions of axons that form connections with other neurons. This is the point where synaptic transmission occurs. It has been estimated that a single neuron is capable of receiving signals from as many as 10,000 other cells. The soma is the body portion of the cell and contains its nucleus and the various organelles required for cellular functions.
Neurons are the primary components of the nervous system, which includes the spinal cord, brain and the central and peripheral nervous systems. Highly specialized types of neurons perform unique functions. Sensory neurons are those that respond to touch, light and sound. Motor neurons activate muscles and glands after receiving signals from the spinal cord and brain. The interneurons connect neurons to each other and form regional neural networks within shared areas of the spinal cord or brain.