Lecture 3 Flashcards
Spinal cord
White matter organized into tracts (bundles of nerve fibers with similar function)
Each tract has a defined beginning and end point
Each tract transmits a specific type of information
Ascending (cord to brain) tracts vs descending tracts (brain to effector neurons)
white and grey matter
butterfly shape grey matter
Discrimination of afferent signals in different tracts
E.g.Vibration, Temperature, Pain, Pressure
Tract named according to
origin and termination
Eg: ventral spinocerebellar tract: ascending, from stretch receptors to spinal chord to cerebellum)
Eg: ventral corticospinal tract, descending, from motorcortex to spinal chord motorneurons, to muscles
Damage to particular areas can interfere with some function, leaving others intact
Defined ascending and descending tracts
Ascending tracts
Descending tracts
In the spinal chord, grey matter is
functionally organized
Dorsal horn
(interneurons)
ventral horn
(efferent motorneurons)
lateral horn
(cell bodies for autonomic control of cardiac and smooth muscle and glands
Spinal nerves:
31 pairs+12 pairs cranial nerves
carry both afferent and efferent fibers, connect via dorsal and ventral root
Cell bodies for afferent fibers: spinal ganglion
Nerve: bundle of peripheral neuronal axons (no neurons)
Spinal cord and dermatome
Each segment of the spinal cord supplies a defined region afferent and efferent –> sensory and motor deficits can be asessed
Sensory region per spinal nerve:
dermatome
Each spinal nerve also contains nerve fibers for internal organs –> referred pain (Head’s zones)
Can have segmental injuries and viral infections
Spinal nerve lesion or peripheral nerve lesion?
Dermatomes vs nerve specific field of sensory innervation
