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20 Cards in this Set

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Following trauma or transection of the spinal cord, all functions are depressed (normal function depends on input from above, with the loss of this input the cord becomes silent). After days, the cord regains its excitability and often become hyperexcitable

This is called _
SPINAL SHOCK
Signs of spinal shock
1. Decrease in arterial blood pressure
2. Areflexia – lasts for weeks to months
3. Loss of bladder/colon control – returns after a few weeks
Name descending motor tracts
1. Corticonuclear and Corticospinal tracts – “nuclear” refers to brainstem nuclei
2. Rubrospinal tract
3. Reticulospinal tract
4. Vestibulospinal tract
5. Tectospinal tract
Course of corticospinal and corticonuclear tracts
1. Begin in cortex
2. Enter posterior limb of internal capsule
3. Middle third of cerebral peduncle (crus cerebri)
4. Basilar pons
5. Pyramids (in the medulla about 90% of the axons cross the midline – decussation of the pyramids)
6. Lateral funiculus of spinal cord
Motor nuclei of cranial nerves – mainly bilateral, except for ?
Facial, nucleus ambiguus, hypoglossal and spinal accessory
Axons of corticospinal tract that cross midline in medulla comprise _ - majority 90%

Axons that cross at the level of their termination in spinal cord form _
LATERAL CORTICOSPINAL

ANTERIOR CORTICOSPINAL
Where are the synapses of corticospinal tract mainly occur
THE SYNAPSES OCCUR MAINLY ON INTERNEURONS – indirectly activate both α and γ motor neurons. However, some contact is made directly to α motor neurons.
Terminations of CNT and CST
-Red nucleus – ipsilateral
-Reticular formation – bilateral
The major input to the red nucleus is from ?
basal nuclei, cerebellum and cerebral cortex
Axons of the rubrospinal tract derive from the magnocellular region of the red nucleus and immediately decussate in ?
VENTRAL TEGMENTAL DECUSSATION
RUBROSPINAL TRACT AXONS descend in close proximity to _ tract and control _
CBST

Distal muscles used in fine, precise movement
Terminations of rubrospinal tract occur on _
1. Oculomotor, trochlear, abducens, facial, trigeminal, vestibular and dorsal column nuclei
2. interneurons to excite α and γ FLEXORS in cervical and upper thoracic cord
The reticulospinal tract arises from a population of cells within the brainstem tegmentum and innervates ?
Alpha and gamma motor neurons
Function of reticulospinal tract
To coordinate posture and movements by integrating vestibular and other sensory input with commands from the cerebral cortex
The medullary (lateral) reticulospinal tract descends ipsilaterally to all cord levels and facilitates
FLEXORS
The pontine (medial) reticulospinal tract descends mainly ipsilaterally to all spinal levels and facilitates?
EXTENSORS
Input to the cells of origin of reticulospinal tracts arise from ?
Spinal cord (sensory input via spinoreticular tract), cerebellum and cerebral cortex.
The reticulospinal tracts are involved in WHAT KIND OF MOVEMENTS
Stronger, sustained, forceful contractions, that are under cortical control.
- Although the medullary system is associated flexors and pontine with extensors, the reticulospinal system in general is BIASED TOWARDS?
EXTENSORS
The vestibulospinal tracts arise from the vestibular nuclei:
• The lateral and inferior vestibular nuclei provide _ that projects to _
and is associated with _
LATERAL VESTIBULOSPINAL TRACT

to all levels of the cord in the anterior funiculus

paravertebral muscles and proximal limb extensors; facilitates extensor neurons