1. Meninges (sing. meninx)
Membranes that line the CNS (brain and spinal cord)
Three layers
Dura mater—outermost
Arachnoid mater—middle
Pia mater—inside layer
Cerebrospinal fluid (CSF)—in subarachnoid space

2. Spinal Cord
The slender nerve column that passes from the brain to the bottom of the vertebral canal
Begins where tissue leaves the foramen magnum
31 segments that give rise to spinal nerves

3. Spinal cord Gray matter-unmyelinated White matter—myelinated
Nerve tracts—bundles of myelinated nerve fibers that make up major nerve pathways
Central canal-contains CSF

4. Cross Section of a spinal cord

5. Spinal Cord Functions
Conduct nerve impulses into and away from peripheral nerves
Ascending tracts carry sensory information to the brain
Descending tracts conduct motor impulses from brain to muscles or glands
Center for spinal reflexes
Reflex arcs that do not travel to brain