terms describing grey and white matter

nuclei

• clusters of grey matter located deep in the brain

• large and defined boundaries

locus

small and defined boundaries

substantia

large, but not defined boundaries

ganglia

clusters of cell bodies outside brain and spinal cord

cortex

• consists of grey matter on surface of the brain

• organized and has layers → allows for complexity

• most evolved

fiber

• aka axon

• long projection of nerve cell that transmits electrical impulses away from cell body

tract

neural pathways that are located in the brain and spinal cord

• runs bilaterally → one on each side of cerebral hemispehre

• some cross over to ascend/descend on the other side

plexus

bundle of nerves outside brain and spinal cord

grey and white commissures

connect the two halves of the spinal cord

• axons that cross from one side of the spinal cord to the other

central canal

• center of grey commissure

• circulates cerebrospinal fluid produced by ependymal cells in ventricles of the brain

nerves

bundles of axons and CT sheaths in PNS