Nerve cells are referred to as neurons. They are located not only within the brain, but extend through the spinal cord and throughout the rest of the body. There are four distinct types of neurons and their structures vary depending on where they are located within the body and what function that they perform. Under the microscope, they can appear almost scorpion-like, with extensions similar to legs at one end and one large extension which is similar to a tail-piece. I’ll be discussing the structures of the neuron further in the page Structure of a Neuron.
The picture alongside illustrates the four types of neurons. Bipolar neurons are also known as interneurons and they interconnect within the brain and spinal cord, hence allowing information to be passed between different sectors of the brain and the spinal cord in a matter of microseconds. Unipolar neurons transmit sensory data from different extremities toward the central nervous system, and the multipolar neurons transmit information from the brain to the skin, muscles and glands of the body. Pyrimidal cells are located purely within the brain, and are particularly prevalent within the cerebral cortex, the hippocampus and in the amygdala. Without pyramidal cells, it would be like the brain is forced to run on dial-up instead of broadband; these cells allow a significantly greater amount of connections to be made, hence dramatically lessening the time that a message gets sent from one part of the brain to the next.