Anatomy Unit 4 Organization of the Nervous System

central nervous system

-brain & spinal cord

-integrates info from PNS & coordinates and influences activity of all parts of the body

peripheral nervous system

-31 pairs of spinal nerves & their branches, 12 pairs cranial nerves & their branches, plexuses, ganglia

-provides info to CNS about internal and external environment

-divides into somatic & autonomic nervous systems

neurons

excitable cells

neuroglial cells

supportive cells

basic neuron structure

-1 neuronal cell body (soma) where cells live

-neuronal processes:

1+ dendrites (receive info)

1 axon (send signals) has mylein sheath

CNS collection of bodies

nucleus

CNS collection of axons

tract or fasciculus

PNS collection of bodies

ganglion

PNS collection of axons

spinal nerve

white matter

composed primarily of myelinated axons-integration

gray matter

composed of neuronal cell bodies, dendrites, unmyelinated axons, & neuroglia

basic patterning of CNS

central cavity surrounded by gray matter which is surrounded by white matter

patterning of gray & white matter in spinal cord

central cavity surrounded by a gray matter core with white matter external to gray matter

patterning of gray & white matter in brain

similar to spinal cord but with additional areas of gray matter:

scattered gray matter is seen within the white matter

-cerebrum & cerebellum also have outer layer of gray matter called cortex