07.3D U7P2 (Part D) Peripheral Nervous System

White Matter

Myelinated fibers (tracts) that consist of mostly axons with myelin sheaths

Gray Matter

Unmyelinated fibers and cell bodies

Dorsal Horn

A longitudinal subdivision of gray matter in the dorsal part of each lateral half of the spinal cord that receives terminals from some afferent fibers of the dorsal roots of the spinal nerves

Ventral Horn

A longitudinal subdivision of gray matter in the anterior part of each lateral half of the spinal cord that contains neurons giving rise to motor fibers of the ventral roots of the spinal nerves

Central Canal

A canal filled with cerebral spinal fluid that runs down the center of the spinal cord

Meninges

Three layers of connective tissue in which the brain and spinal cord are wrapped

Dorsal Root

Collections of cell bodies from sensory neurons outside the central nervous system that are associated with the dorsal root ganglia

Ventral Root

Collections of cell bodies from motor neurons outside the central nervous system that are associated with ventral root ganglia

Endoneurium

Connective tissue covering that surrounds and protects each neuron

Perineurium

The layer of connective tissue that surrounds a fascicle within a peripheral nerve

Fascicles

Bundles of axons

Epineurium

Connective tissue that surrounds nerves
Dense connective tissue that surrounds entire nerve including fascicles and blood vessels