Exam Two - GSA for Cranial Nerves Flashcards
All somatosensory fibers from cranial nerves return to the sensory nuclei of the ________, regardless of the cranial nerve origin
trigeminal nerve
GSA fibers of vagus carry…
pain, temp, and touch sensations from the posterior cranial fossa, post. ear, external auditory meatus, pharynx, and posterior and the external surface of the tympanic membrane
GSA fibers from 9 carry…
general sensory info (pain, temp, touch) from the skin of external ear, internal surface of typanic membrane, walls of upper pharynx, and post 1/3 of tongue, anterior surface of epiglottis and vallecula
Which nerve controls the muscles of facial expression and the stapedius muscle?
facial
which nerve controls the activity of most of the glands of the head (except parotid)?
facial
which nerve carries taste from the anterior 2/3 of tongue?
facial
Where do the GSA fibers of facial nerve originate?
originate in pain, temp, and tactile receptors of a small area of skin near the external ear
Where are the cell bodies located for the GSA portion of facial nerve?
geniculate ganglion
where do the GSA fibers of facial nerve terminate?
principal and spinal trigem nuclei
Where fo the SVE fibers of facial nerve originate?
facial motor nucleus in the pons
What are the SVE fibers of facial nerve responsible for?
form the motor root of NC 7 that supplies the muscles of facial expression
Where is the nucleus of facial CN located?
caudal pons
The caudal pans contains the cell bodies of ______ fibers of CN7
SVE
(innervate muscles of facial expression and stapedius)
- contains a subnucleus for each muscle it supplies
- receives input from cortex and other CN
direct input from the cerebral cortex to facial CN is via the ________________
corticobulbar tracts
subnuclei supplying muscles from the ______ receive inputs from the corticobulbar tracts of both sides
upper half of the face
subnucleir supplying muscles of the ______ receive corticobulbar inputs only from the contralateral side
lower half of the face
facial CN receives input from other CN nuclei which are important in ________
reflexes
facial CN receives input from other CN nuclei which are important in what reflexes
- input from sensory nuclei of CN 5 (sucking reflex in babies)
- inputs from the superior olivary nucleus (reduce loud noise by contracting stapedius)
- inputs from the superior colliculus ( closure of the eyelids in response to bright light or a rapidly approaching object)
unilateral lesions of CN 7
- paralysis of muscles of facial expression on ipsilateral side of the face
- absence of secretions from the lacrimal gland of the ipsilateral eye
- sensitivity to loud sounds ipsilaterally
- no secretions from the sublingual and submandibular glands
- loss of taste on ant 2/3 tongue and palate
- ipsilateral absence of mucous secretions (drying) of nose)
sensory information from craniofacial structures including oral and nasal cavity
GSA CN 5
face, scalp and top of head
GSA CN 5
conjunctiva, tounge, teeth, external portion of tympanic membran
GSA CN 5
TMJ
GSA CN 5
meninges of ant and post cranial fossa
GSA CN 5
innervates muscles of mastication
SVE CN 5
tensor tympani, tensor palatini, mylohyoid, ant belly diagastric
SVE CN 5
What are the peripheral components of the trigem nerve?
- opthalmic
- maxillary
-mandibular - semilunar
- sensory and motor roots
central components of the trigem nuclei in brainstem
mesencephalic
pontine (principal)
spinal
motor
The cell bodies of trigeminal primary afferent neurons are in the…
trigeminal ganglion and mesencephalic nucleus
the central processes of trigem ganglion neurons form the large _______ of the trigem nerve before entering the pons
sensory root
second order neurons for trigem system are in the brainstem’s
trigem sensory nucleir
ascending branches from first order neuron (trigem) terminate in the ___________ located in the pons
principle sensory nucleus
decending branches of trigem form the _______-
spinal tract of trigem
the principle sensory nucleus, the trigem mesencephalic nucleus and their connections are primarily involved in…
tactile discrimination, proprioception, and kinesthesia from the head
mesencephalic and principle trigem is like DCML or ALS?
DCMS
spinal trigem is like DCML or ALS?
ALS
mesencephalic nucleus purpose
proprioception and muscle stretch reflex
pontine nucleus purpose
discriminative touch, vibration and proprioception
spinal trigem purpose
thermal, non-discriminative tactile, nociceptive inputs
motor trigem purpose
SVE and muscle stretch reflex (jaw jerk)
the principle sensory trigem nucleus is divided into the:
- dorsomedial division
- ventrolateral division
second order neurons in the anterior trigeminothalamic tract relays discriminative tactile info from the _________ to the ________
head, VPM
dorsomedial division
input from the oral cavity
ventrolateral division
input from all 3 components of trigem
neurons in the VL part of the principle sensory nucleus project to the ________ along with fibers from the _______ trigem nucleus. this combined ascending projection forms the __________
contralateral VPM, spinal
anterior trigemino-thalamic tract
neurons in the dorsomedial division of the principle sensory nucleus project to the _______
ipsilateral VPM - posterior dorsal trigemino-thalamic tract
the afferent projections from the principal terminate _________ within the _________.
oral cavity is represented _______
external facial structures represented ___________-
somatotopically, VPM
medially
laterally
____________ project via the posterior limb of the IC to S1 in the postcentral gyrus
third order thalamocortical neurons
____ have the highest peripheral innervation density, and largest representation in the postcentral gyrus
perioral regions
the primary afferent neurons for the mesencephalic trigemthalamic trac are located in the…
trigem mesencephalic nucleus
mesencephalic tract fibers connect to….
trigem motor neurons
reticular formation
spinal trigeminal nucleus
cerebellum
blood supply for the thalamus
thalamogeniculate arteries
thalamogeniculate arteries are a branch of which artery?
PCA
compromise of the thalamogeniculate arteries result in the loss of tactile sensation from the…
contralateral body and head
GSA from facial?
small area behind ear
GSA from glossopharyngela
GSA to post 1/3 tongue, skin of external ear, internal surface of tympanic membrane, external membrane
GSA from vagus
skin back of ear, external acoustic meatus, external surface of tympanic membrane and pharynx
shingles is a viral disease with ______. after a bout of chickenpox, viral DNA becomes latent in ____________.
dermatomal distribution, trigem ganglia and DRG cells
