Nervous System

Central Nervous System (CNS)

Brain and spinal cord

Peripheral Nervous System (PNS)

Nerves

Autonomic Nervous System (ANS)

Part of the PNS that controls parts of your body automatically

Neurons

Nerve Cells

Glia

Support Cells

Cell Body

Main part of neuron

Dendrites

Receive signals

Axon

Sends signals

Sensory (afferent) Nuerons

Send signals to the CNS

Motor (efferent) Neurons

Sends signals from the CNS to the rest of the body

Interneurons

Neurons that conduct signals from sensory to motor neurons

Myelin

White, fatty wrapping that covers the axon

Schwann Cells

Form myelin in PNS

Nodes of Ranvier

Spaces between Schwann cells

Neurilemma

Outer membrane of Schwann cells

Astrocytes

Star-shaped glia that attach neurons to blood vessels

Blood-Brain Barrier (BBB)

Separates blood from nervous tissue

Microglia

Digest microbes and dead neurons

Oligodendrocytes

Hold neurons together, includes Schwann cells

Nerves

Bundled nerve fibers in the PNS

Tracts

Bundle of axons in the CNS

White Matter

Tracts with myelinated axons

Gray Matter

Cell bodies and axons that are not myelinated

Endoneurium

Thin membrane covering each membrane

Fascicle

Bundle of nerve fibers

Perineurium

Thin membrane that surrounds each fascicle

Epineurium

Thick membrane that surrounds the whole nerve