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. Imagine a single cell able to make decisions about up to 100,000 inputs and multiply it by over 10 billion cells and you begin to grasp the complexity of the nervous system and the challenge that neuroscientists face as they investigate its role in behavior. A much larger extension attached to the soma is the axon . The soma narrows rapidly in an area called the axon hillock and becomes a long narrow tubular structure, the axon. The axon is the portion of the cell that communicates with other neurons.