NB19 Pain pathways of head and neck reflexes Flashcards
Corticobulbar fibres directly innerate lower motor neurons (α and γ) via____a__________
Indirect innervation is done mostly through ________b______
a= motor nuclei of cranial nerves
b) pontine and medullary reticular formation (equivalent to interneurons of spinal cord)- the reticular formation contains pattern generators that set up patterened activity.
What are the corticobulbar fibers?
cortex sends axons to cranial nerve motor nuclei in brainstem (bulb)
Why does a unilateral lesion of the corticobulbar fibers to motor 7 effect the face the way it does?
weakness of the
muscles of expression of the face BELOW THE EYE ON THE SIDE CONTRALATERAL TO THE
LESION.
Not weak above the eye as BILATERAL (crossed and uncrossed) corticobulbar
projections from the cerebral cortex influence the lower motor neurons (within Motor VII) innervating the
frontalis muscle and orbicularis oculi,
Weak bellow the eye as
Only CROSSED corticobulbar projections influence the lower
motor neurons innervating the muscles of the LOWER face
What effect on movement would a lesion on the left motor cortex of the corticospinal and corticobulbar fibers to motor 7, nucleus ambiguous and hypoglossal nucleus?
Right hemiplegia and tongue will deviate to the right upon protrusion.
Lower facial mm. on RHS will be weak
1) Upper motor neuron lesion if 12 on RHS results in tongue deviating to:
2) Lower motor neuron lesion if 12 on RHS results in tongue deviating to:
1) tongue deviation contralateral to lesion, so to left
2) tongue deviation ipsilateral to lesion (e.g. right lesion of XII nucleus = tongue goes to right), ???????????
e. g. right lesion of XII nucleus = tongue goes to right), (right lesion of corticobulbar pathway = tongue goes to left)
the glossopharygeal nerve has an ________
ipsilateral projection.
2, 4 and 6 control movement of __a___ and have
a) eye
cranial 12 is _____a____ except when providing ____b_____, explaining deviation of tongue ____c____to lesion.
a) bilateral
b) genioglossus
c) ipsilateral
Name the pain afferent for:
1) face, nose, meninges and muscles of mastication
2) ear canal
3) meninges, ear canal , larynx
4) neck, meninges in post cranial fossa
1) trigeminal
2) facial
3) vagus
4) glossopharyngeal
5) cervical spinal nerve
What pain fibre are part of the plexus of raschkow providing pain from teeth:
1) A-fibres ( are myelinated), have fibers extening to most dental tubules, theorised movement of fluid in dentinal tubules triggers pain sensation
2) C-fibres, ache pain, unmylinmated , terminate in pulp tissueas free nerve ending or in blood vessels
Where is the sensory aspect of pain procesed?
2) where is the emotional distress of pain processes?
1) samatosensory cortex
2) anterior cingulate cortex
What grey matter is involved in descending modulation of pain and in defensive behaviour?
Grey matter located around cerebral aqueduct within tegmentum of midbrai, called the periaquaductal grey matter
What happens in the anterior cingulate cerebral when we experience empathy?
empathy elicits activity only in the ACC.
How does the periduct
1) It release enkephalin and 5-HT
2) The 5-HT released from raphe nucleus descends and binds to receptors in dorsal root of spinal cord.
2) It binds to inibitory neurones in laminae 2 ( i.e. substantia gelatinousa)
3) the interneuonres release either enkaphalin or dynorphin (form of morphine) which binds to mu opioid receptors
What are opoid receprtors involved in?
modulation of pain
