A. Perikarya—nerve cell body

B. Axon—transmits neural signal to other neurons or to the organ/muscle

C. Dendrite—receives neural input from other neurons

D. Oligodendrocytes—type of glial cell (neural support cell) responsible for myelination of nerves within the CNS

E. Schwann cell—type of glial cell (neural support cell) responsible for myelination of nerves within the PNS

F. Myelin—a lipid-rich coating around the neural axons. Produced by Schwann cells (PNS) and oligodendrocytes (CNS). Upon gross inspection, myelin is white and responsible for the “white matter” color of the brain and spinal cord.

G. Ganglia—a cluster of perikarya located outside the CNS

H. Nuclei—a cluster of perikarya located within the CNS

I. Nissl bodies—large granular bodies found in neurons. They are endoplasmic reticulum responsible for protein synthesis.

J. Node of Ranvier—gaps in the myelin sheath. The action potential signal jumps along the axon from node to node for more rapid signal propagation.

K. Most nerve cell bodies (perikarya) are found within the CNS, but sensory (afferent) and autonomic (visceral motor) neurons are found outside the CNS as clusters called ganglia. Sensory (afferent) perikarya are located in the dorsal root ganglia, near but not technically in the CNS.

L. Perikarya of the autonomic nervous system (sympathetic parasympathetic) are located outside the CNS. Sympathetic perikarya are found in ganglia near the spinal cord, and parasympathetic ganglia are found in the target organ.