Lecture 9 Flashcards
(47 cards)
What 2 types of fibers do cranial nerves consist of?
Efferent motor and afferent sensory fibers
Efferent motor fibers vs. Afferent sensory fiber origins
efferent motor fibers: originate in the nuclei of the brainstem:: afferent sensory fibers: originate in the peripheral ganglia (trigeminal ganglia)
Cranial nerves receive bilateral UMN innervation. T or F?
True
w/ the exception of portions of CN V, VII, & XII
Corticobulbar pathways cross over at the level of _________.
the CN nuclei
Trigeminal nerve (CN V) is not a mixed nerve. T or F?
False; it is a mixed nerve.
It has both motor and sensory functions.
Where do the motor and sensory roots of the trigeminal nerve attach?
The Pons
motor roots vs. sensory pathway nuclei (CN V)
motor nuclei: restricted to Pons:: sensory pathways: cell bodies in trigeminal ganglia & terminate in trigeminal sensory nucleus
What muscles does the trigeminal nerve innervate?
- muscles closing/ opening the jaw
- muscle of velopharyngeal closure
- muscle tensing in the tympanic membrane
Sensory innervation of the Trigeminal nerve
Opthalmic nerve, maxillary nerve, mandibular nerve
What are the the 5 functions of the Trigeminal nerve?
- Mastication
- Articulation
- Tensing/closure of the soft palate
- hyolaryngeal elevation
- sensation to the face, teeth, gums, & anterior 2/3 of the tongue
(MATHS)
During trigeminal nerve motor testing where the jaw is supposed to open freely against resistance, the jaw will deviate towards the weak side of what muscle?
pterygoid muscle
weakness of the lateral pterygoid is expressed as ?
difficulty moving in the opposite direction
unilateral UMN damage vs. unilateral LMN damage (CN V)
unilateral UMN damage: no significant motor defecits :: unilateral LMN damage: mandible deviates towards side of paralysis or paresis during opening; hyptonia & atrophy; impaired hyolaryngeal elevation
bilateral UMN damage vs. Unilateral LMN damage (CN V)
bilateral UMN damage: hypertonia; slow movements; restricted jaw opening/closing; reduced hyolaryngeal elevation :: bilateral LMN damage: hypotonia; impaired jaw opening/closing; impaired hyolaryngeal elevation
(note: HYPERtonia vs HYPOtonia)
The facial nerve (CN VII) is a mixed nerve, T or F?
True; both motor and sensory functions.
Roots are attached to the PONS.
motor pathways vs. sensory pathways (CN VII)
motor pathways: begin in facial motor nucleues in pons :: sensory pathways: cell bodies in geniculate ganglion; terminate in tractus solitarius (taste) nucleus and trigeminal nerve spinal nucleus (touch)
The facial nerve’s motor branches innervate…
- the muscles of facial expression
- platysma
- stylohyoid
- stapedius
- post. belly of digastric.
(note: the visceral motor branches innervate the lacrimal, submandibular and sublingual glands.)
What two senses do the sensory branches of the Facial nerve innervate?
- special sensory: taste for the ant. 2/3 of tongue, floor of mouth and palate
- touch: external ear and auditory meatus
What are the 4 functions of the facial nerve?
- Movements of facial expression
- supports hyolarngeal elevation
- saliva & tear production
- taste 2/3 of tongue
Two tests for motor testing of facial nerve?
test for facial symmetry
test motor function for upper/lower face
Unilateral UMN damage leads to upper face weakness. T or F?
False; no upper face weakness occurs b/c it is bilaterally innervated.
Contralateral lower face weakness occurs instead.
Bilateral UMN damage leads to ________ of the whole face.
spastic paralysis
Glossopharyngeal nerve (CN IX) Anatomy
- emerges from the medulla
- motor portions originate in nucleus ambiggus in medulla
-sensory components are processed in the nucleus solitarius in the medulla
Motor vs. sensory innervation of glossopharyngeal nerve
motor: innervates the stylopharyngeus muscle:: sensory: post. 1/3 of the tongue, soft palate
