Thanks to these researchers working in the late 1800s and early 1900s, we now know that, with only a small number of exceptions, neurons are individual cells which communicate with each other chemically across microscopic gaps between one cell and the next. Click on the image at the left to get a larger version. The neuron consists of several distinctive regions which are all parts of the cell. The outer membrane consists of fat molecules which are able to selectively block or pass molecules. The nucleus is a structure containing the cell's chromosomes.
Mitochondria provide the cell with energy through metabolism.
Ribosomes synthesize protein molecules used by the cell and which are transported to other sites within the cell by the endoplasmic reticulum . If the cell body is damaged, the cell cannot survive. Attached directly to the cell body or narrow, often hairlike, extensions called dendrites . Dendrites are the primary receiving sites for incoming irritation in most neurons. Some dendrites also have even smaller spines which serve as extremely sensitive receptors.