13-3 Gray Matter and White Mater Flashcards
Describe the Gray matter
cell bodies of neurons, neuroglia, and
unmyelinated axons
Describe the white matter
myelinated and unmyelinated axons
State the horn regions in the gray matter
- Posterior horns—somatic and visceral sensory nuclei (incoming information from receptors)
- Anterior horns—somatic motor nuclei (outgoing information to effectors)
- Lateral horns—thoracic and lumbar segments; visceral motor nuclei
Describe the Gray commissures
Gray commissures
– Narrow bands of gray matter around central
canal
– Axons cross here to the other side of spinal cord
Describe the structural organization of the white matter
Three columns (regions)
* Posterior white columns—between posterior
horns and posterior median sulcus
* Anterior white columns—between anterior horns and anterior median fissure
– Anterior white commissure—where axons
cross from one side of the spinal cord to the other
* Lateral white columns—on each side of spinal cord, between anterior and posterior columns
Tract—a bundle of axons in CNS
* Relay the same type of information in the same direction
* Ascending tracts—sensory information up toward
the brain
* Descending tracts—motor commands down to the spinal cord