Neuron Anatomy

Soma (Cell Body)

Contains the cell nucleus; receives input via dendrites and processes it; clusters of soma appear gray (gray matter)

Dendrites

Tree-like extensions of the soma that receive input from other neurons and transmit signals toward the soma

Axon

Long process that conducts electrical signals away from the soma to the target cell.; most neurons have only one axon; covered in myelin, making axon bundles appear white

Axon Hillock

The junction between the soma and axon where action potentials are initiated; contains voltage-gated ion channels

Myelin Sheath

Lipid-rich insulating layer that wraps around an axon; produced by oligodendrocytes (CNS) or Schwann cells (PNS); speeds up signal transmission; gives axon bundles a white appearance

Nodes of Ranvier

Gaps (unmyelinated segments) between successive myelin sheaths along an axon; action potentials 'jump' between nodes (saltatory conduction)

Synapse/Synaptic End Bulb

Junction where one neuron communicates with another cell; the axon terminal (synaptic end bulb) releases neurotransmitters into the synaptic cleft