extends from foramen magnumto the level of the second lumbar vertebrae

-shorter than vertebral column because vertebral column grows faster than spinal cord

-dura mater: single layered and not attached to the bony vertebrae

--epidural space: between dura mater and vertebrae

---filled with adipose and blood vessels

in the subarachnoid space is cerbrospinal fluid

-lumbar puncture: between L3 and L4 or L4 and L5 for cerebrspinal fluid diagnosis or to introduce anesthetics

organized into horns and commissures

-posterior gray horn: contains cell bodies of interneurons which have synapsed with sensory neurons

-dorsal root: connection to spinal cord from the peripheral nervous system that carries only sensory information and ends at posterior gray horn

-dorsal root ganglia: cell bodies of sensory neurons (unipolar neurons)

contains cell bodies of motor neurons

-ventral root: connection from the spinal corf to the peripheral nervous system that carries only motor information

-motor neurons: multipolar neurons

gray communication between right and left section of cord anterior to the central canal

-posterior gray commissure: gray communication between right and left section of cord posterior to the central canal

organized into columns and commissures (tracts travel in columns)

bundles of axons in the pns

-surrouned by connective tissue

-epineurium: around whole nerve

-perineurium: around a fascile of nerve fibers

-endoneurium: around a single axon

1. visceral

2. posterior

3. anterior

afferent

(goes up to brain)

efferent

(going down)