Intro | Axon | Axon Hillock | Dendrites | Myelin Sheath | Nodes of Ranvier | Soma | Synapse | Terminal Buttons
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The Soma (Latin, som / a: body) or cell body of a neuron contains the nucleus and other structures common to living cells. These structures support the chemical processing of the neuron; the most important of which is the production of neurotransmitters.
In addition to the nucleus, the soma contains other cellular organelles; structures with distinctive structure and function that are found within all living animal cells. These organelles float within the cell boundary or cell membrane in a fluid called c ytoplasm. Organelles include ribosomes (site of protein production), mitochondria (site of energy production), endoplasmic reticulum (a network of tubes used to transport proteins throughout the cell), lysosomes (containing enzymes that breakdown cellular substances for recycled use), and Golgi complex (a network of vesicles or sacs that prepare hormones for secretion). The soma is, therefore, the site of major metabolic activity in the neuron. The size of neuronal somas range widely from 0.005 mm to 0.1 mm in mammals. Collections of cell bodies (somas) give the grayish appearance to the gray matter of the brain. Pigment-containing proteins are found in high concentration in the nucleus and other cell structures of the soma, creating this coloration.