The document discusses the structure and function of nerve cells (neurons). It defines the nerve cell as the basic unit of the nervous system. The key parts of a nerve cell are then enumerated and defined, including the cell body, nucleus, dendrites, axon, axon terminals, node of Ranvier, Schwann's cells, myelin sheath. Nerve cells allow communication between different parts of the body through electrical signaling along their axons and at synaptic connections. They are essential for controlling functions throughout the nervous system.