N brain contains btw 10billion and 100billion nerve cells and as many helper cells (take care of important support and housekeeping functions) There are many types of nerve cells (shape, size, chemicals they produce) N pierre flourens emphasized that different parts of the nervous system were responsible for different functions. N donald hebb considered how individual nerve cells are organized into larger units; proposed principles of organization by which these units were organized, suggested they could generate memory, thought, decision making. N nerve cells of the brain are organized in modules: clusters of nerve cells that communicate with eachother. Central nervous system: the brain and spinal cord. Spinal cord: a long, thing collection of nerve cells attached to the base of the brain and running the length of the spinal column. Nerve: a bundle of nerve fibres that transmit info btw the central nervous system and the body"s sense organs, muscles, and glands.