Soma (biology)

Portion of a brain cell containing its nucleus Dendrite Soma Axon Nucleus Node ofRanvier Axon terminal Schwann cell Myelin sheath Soma In cellular neuroscience, the soma (pl.: somata or somas; from Greek σῶμα (sôma) 'body'), or cell body, is the bulbous, non-process portion of a neuron or glial cell that contains the cell nucleus. The part of the soma without the nucleus is called the perikaryon (pl.: perikarya). Cell body of a neuron containing the nucleus. Ultrastructure The soma of a neuron (i.e., the main part of the neuron in which the dendrites branch off of) contains many organelles, including granules called Nissl granules, which are composed largely of rough endoplasmic reticulum and free polyribosomes. The cell nucleus is a key feature of the soma. The nucleus is the source of most of the RNA that is produced in neurons. In general, most proteins are produced from mRNAs that do not travel far from the cell nucleus. This creates a challenge for supplying new proteins to axon endings that can be a meter or more away from the soma. Microtubules and neurofilaments Axons contain microtubule-associated motor proteins that transport protein-containing vesicles between the