PowerPoint on spinal cord and grey/white matter
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Transcript PowerPoint on spinal cord and grey/white matter
Spinal Cord as part of the
Nervous System plus
Grey & White matter
Already know the reflex arc
A few more parts to add
Gray and White Matter of the CNS
(GROSS ANATOMY OF THE CNS)
Gray matter: gray-colored
Where neuron cell bodies are clustered
White matter: white-colored
Where millions of axons are running between
different part of CNS, in bundles of “tracts”
Remember, tracts are in CNS, vs nerves in PNS
White is from the myelin sheaths
Usual pattern of gray/white in CNS
White exterior to gray __________________
Gray surrounds hollow
central cavity ______________________________
Two regions with additional
gray called “cortex”
______________
Cerebrum: “cerebral cortex”
Cerebellum: “cerebellar cortex”
(pic from Marieb lab book p 263)
Gray/White in spinal cord
Hollow central cavity (“central
canal”)
Gray matter surrounds cavity
White matter surrounds gray
matter (white: ascending and
descending tracts of axons)
“H” shaped on cross section
Dorsal half of “H”: cell bodies of
interneurons
Ventral half of “H”: cell bodies of
motor neurons
No cortex
Same pattern
Dorsal (posterior)
white
gray
Central canal_____
Ventral (anterior)
Spinal cord cross section
Grey Matter vs White Matter
1. Grey matter is made up of nerve cell bodies while white matter is made up of fibers.
2. Unlike the white matter, the neurons of grey matter do NOT have extended axons.
3. Grey matter occupies 40 percent of the brain, while white matter fills 60 percent of
the brain.
4. Grey matter has this color because of the grey nuclei that comprises the cells. Myelin
is responsible for the white appearance of the white matter.
5. Grey matter has NO myelin sheath, while white matter is myelinated.
6. Processing is concluded in the grey matter, while white matter allows
communication to and from grey matter areas, and between the grey matter and the
other parts of the body.
Basic neuronal
organization
Anterior view
Coronal section
of cerebrum
Cross sections
of spinal cord
and brains stem
Note gray
matter (brown)
and white
matter (tan)
Reflex arc and
information
processing are
shown