Lecture 8 - Cranial Nerves V and VII Flashcards
The trigeminal nerve (CN V) consists of what 2 types of nuclei?
- somatic sensory
- branchial motor
The somatic sensory trigeminal nerve (CN V) nuclei whose peripheral fibers supply the skin and deep tissues of the head and dura are the ______ and _____ _____ nuclei. The somatic sensory CN V nucleus that supplies peripheral muscle spindles and other mechanoreceptors is the _______ nucleus.
- spinal
- main sensory
- mesencephalic
The branchial motor trigeminal nerve (CN V) nucleus whose peripheral fibers supply the MOM, tensor tympani, and several other muscles is the ______ ______ nucleus. It forms the _____ limb of the jaw-jerk reflex.
- trigeminal motor
- efferent
- innervated muscles = “MOM & the tensor twins.” These are the muscles of mastication, tensor tympani, tensor veli palatini, as well as the mylohyoid and anterior belly of the digastric muscles
What 4 types of sensory information does the trigeminal nerve (CN V) transmit to the cortex, cerebellum, and reticular formation?
- tactile
- proprioceptive
- pain
- temperature
The trigeminal nerve (CN V) has 3 branches. The sensory division that supplies the upper face is the ______ division (V1). The sensory division that supplies the middle face is the ________ division (V2). The mixed sensory and motor division that supplies the lower face is the ______ division (V3).
- ophthalmic
- maxillary
- mandibular
Three of the trigeminal nuclei (mesencephalic, main sensory, trigeminal motor) can be viewed from an XS of the middle _____.
pons
The trigeminal SPINAL nucleus sends ascending [contralateral/bilateral] projections to the _____ _____ nucleus of the thalamus. The trigeminal MAIN SENSORY nucleus sends [contralateral/bilateral] projections to the same place. Both then travel through the internal capsule to the ________ ______ of the parietal lobe.
- contralateral
- ventral posteromedial (VPM)
- bilateral
- postcentral gyrus
Sensory fibers of the trigeminal nerve serve the face, oral cavity, teeth, and meninges. These areas transmit sensory info to the trigeminal ______. These then send feedback to the ____ _____ _____ nucleus. Senses included are _____ touch and ______.
- ganglion
- trigeminal main sensory
- discriminative
- vibration
The main trigeminal sensory nucleus is at mid-____ level, and sends a thick ______ of cells through much of the brainstem.
- pons
- column
The trigeminal main sensory nucleus is homologous to the _______ _______ nuclei that receives proprioceptive info from the appendicular skeleton.
- posterior column (PCML)
The trigeminal main sensory nucleus has 2 pathways. The [crossed/uncrossed] pathway joins the medial lemniscus on its way to the ______ _______ nucleus of the thalamus. The [crossed/uncrossed] dorsal trigeminal tract representing the oral cavity goes to the _____ _____ nucleus of the thalamus.
- crossed
- ventral posterolateral (VPL)
- uncrossed
- ventral posteromedial (VPM)
The trigeminal spinal nucleus senses ______, ____ ____, and ________. It is directly ______ of the trigeminal ______ _______ nucleus, and uses similar pathways.
- pain
- crude touch
- temperature
- inferior
- main sensory
- homologous to Lissauer’s tract of the anterolateral spinal pathway (ALP) that transmits the same senses
The trigeminal spinal nucleus is divided into 3 parts based on histology. (Rostral to Caudal)
- _____ nucleus: main sensory nucleus to pontomedullary junction
- _____ nucleus: pontomedullary junction to obex
- _____ nucleus: obex to spinal cord
- oral
- interpolar
- caudal
As part of the spinal trigeminal nucleus the _____ ______, receives input from intraoral and perioral structures. The part of the nucleus directly inferior to this that activates trigemino-autonomic reflexes is the ____ ______ proper. The most inferior of all 3 portions is responsible for pain, crude touch, and temperature sensation - the _____ ______.
- pars oralis
- pars interpolaris
- pars caudalis
Where the spinal trigeminal nucleus transitions from the pars interpolaris to the pars caudalis, there is a lack of ______ organization, and the region responds to and possibly supresses _____ from many areas served by the trigeminal nerve (CN V).
- somatotopic
- pain
The pars caudalis serves both superficial structures like the ______ _____ and teeth, and deep muscles such as the _______, and the ____. The convergence of these structures may be a basis for referred ______.
- oral cavity
- MOM (muscles of mastication)
- TMJ
- pain
Spinal trigeminal fibers join the ______ tract and terminate in the VPM.
spinothalamic
Pars caudalis has a ____ structure with ______ organization. This makes it look like an “_____ _____” representation from rostral to caudal of the peripheral face. Mostly _____ fibers are present here.
- laminar (lamina II)
- somatotopic
- onion peel
- pain
The pars caudalis is in _______ ___ of the substantia gelatinosa, and contains both excitatory and inhibitory interneurons. It receives afferents from CN ____, ___, and ____ for the near ear.
- lamina II
- VII
- IX
- X
The “onion-like” somatotopic arrangement of the pars caudalis is arranged as follows:
- mandibular division (V3): ______
- ophthalmic (V1): _______
- maxillary (V2): _______
- dorsal
- ventral
- in between
Due to the onion-like distribution of sensory loss, the more ______ a spinal trigeminal tract injury, the more sensory function is preserved around the mouth.
caudal
In the tooth pulp (V3), 70-80% of fibers are ____ and ___ for fast and slow pain. 20-30% are _____ for touch and pressure (faster) from the inferior alveolar nerves into the predentin and dentinal tubules of teeth.
- Aδ
- C
- Aβ
In tooth pulp, the sensory fibers project to the trigeminal _____ _____ nucleus and trigeminal _____ nucleus. In the latter, their projections decrease from the pars oralis to the inferior pars caudalis. They also project to the upper cervical _____ ____.
- main sensory
- spinal
- spinal cord
Brief episodes of excruciating pain caused by one or more divisions of the trigeminal nerve is called _____ _____. It is most common in the ____ division.
- trigeminal neuralgia
- mandibular (V3)
Trigeminal neuralgia is often triggered by _____ stimuli. There [is/is not] sensory trouble between attacks. Another possible trigger may be trigeminal compression by a _____ _____ or ______. Possible treatment is cutting the nerve root, which results in a loss of ______ related to the cut root.
- tactile
- is not
- blood vessel
- tumor
- everything (all sensation, not just pain)
Surgical cutting for trigeminal neuralgia is dangerous because it compromises medullary _____ and _____ centers.
- cardiovascular
- respiratory
Vascular-related trigeminal neuralgia is usually the result of the ______ ______ artery. The artery can be reoriented with surgical padding to ______ the trigeminal nerve.
- superior cerebellar
- decompress
The jaw-jerk reflex is mediated by the trigeminal _____ nucleus.
motor
Chewing movements are mediated by the ____-_____ nucleus directly superior to the trigeminal motor nucleus.
supra-trigeminal
The trigeminal _______ nucleus is responsible for ______ (spatial orientation) of the MoM, and for pressure/tension on the ______ ligaments.
- mesencephalic
- proprioception
- periodontal
Since the trigeminal mesencephalic nucleus is sensory for proprioception, it projects to the efferent nuclei responsible for mastication: trigeminal _____ nucleus, and _____-______ nucleus (masticatory generator).
- motor
- supra-trigeminal
The trigeminal ________ nucleus controls the occlusal vertical dimension between the maxilla and mandible.
mesencephalic
Cell bodies of the trigeminal mesencephalic nucleus are ______.
unipolar
Trigeminal (CN V) Nuclei Summary:
- Mesencephalic nucleus: ______ myelination, homologue of the ____ ____ _____ _______ pathway. Function:_______
- Main sensory nucleus: _______ myelination, homologue of the _____ _____ _____ _________ pathway. Function:_______ touch
- Spinal nucleus: ______ myelination, homologue of the ________ system. Functions: ____, ___ touch, _______
- heavy
- posterior column medial lemniscal (PCML)
- proprioception
2.
- heavy
- posterior column medial lemniscal (PCML)
- discriminative
- light
- anterolateral
- pain, crude touch, temperature
The trigeminal motor nucleus has _____ _____ cell bodies. It terminates in the muscles of mastication, and functions to ______ the mandible.
- branchial motor
- close
Trigeminal motor nuclei lesions will cause weakened jaw _____, and will cause the open jaw to deviate [away from/toward] the side of the lesion.
- closure
- toward
The _________ nucleus is actually part of the reticular formation.
supra-trigeminal
The supra-trigeminal nucleus is the _____ _____ ______ for mastication.
rhythmic pattern generator
What are the 4 muscles of mastication?
- temporalis (closing)
- masseter (closing)
- medial pterygoid (closing)
- lateral pterygoid (opening)
The jaw-jerk reflex is ________, or has only one synapse. It is activated by a downward tap on the chin that stretches the _______ muscles. The afferent limb of the trigeminal _________ nucleus receives the signal, while the efferent limb of the trigeminal _______ nucleus triggers mandibular closure. Damage to _____ ____ _____ enhances this reflex.
- monosynaptic
- masseter
- mesencephalic
- motor
- upper motor neurons (UMN)
What 4 types of nuclei are part of the facial nerve?
- somatic sensory (SS)
- visceral sensory (VS)
- visceral motor (VM)
- branchial motor (BM)
The facial nerve (CN VII):
- ______ _____ nucleus: pairs with the geniculate ganglion and serves the outer ear
- Nucleus of ______ _____: pairs with geniculate ganglion, serves the taste buds/anterior 2/3 of tongue, parts of nasal cavity and soft palate
- _____ ______ nucleus: pairs with submandibular & pterygopalatine ganglia, serves the following glands: submandibular, sublingual, nasal, palatine, lacrimal
- ______ _____ nucleus: serves muscles of facial expression and the stapedius
- spinal trigeminal (SS)
- solitary tract
- superior salivatory
- facial motor
The facial nerve (CN VII) has many functions. The muscles of _____ _____ close the eyes and lips. The volume of sounds are modulated by the _____ muscle. The anterior 2/3 of the tongue is provided with ______. The eyes are provided with tears through _______, and the sublingual/submandibular/parotid glands are stimulated to ______.
- facial expression
- stapedius
- taste
- lacrimation
- salivate
Somatic sensory fibers of the facial nerve supply the skin of the outer ____. Fibers enter the dorsomedially situated _____ _____ tract.
- ear
- spinal trigeminal
The facial _____ ______ nuclei supply the muscles of facial expression.
branchial motor
Motor neurons to _____ facial muscles mainly innervated by contralateral cortex, but ______ facial muscles innervated bilaterally. Unilateral damage to the _________ pathway results in inability to smile or bare teeth symmetrically.
- lower
- upper
- corticobulbar
Corticobulbar lesions results in selective weakness of _____ facial muscles.
lower
Paresis of facial muscles above and below the eyes, localized on one side of the face, leading to reduced salivation & lacrimation and hyperacusis of the stapedius is known as ______ ______.
Bell’s Palsy
If the cornea is touched, both eyes blink. This is known as the _____ ______ reflex. The _____ limb of this reflex sends information from the trochlear nerve to the trigeminal spinal nucleus. The trigeminal spinal nucleus & reticular formation then stimulate the _______ limb through bilateral projections of the ______ nerve. This can be used as a clinical test for cranial nerves ___ and ___.
- corneal blink
- afferent
- efferent
- facial
- V
- VII
The jaw _____ reflex is done when food comes into contact with oral membranse. The jaw ______ reflex is done when periodontal ligament afferents are activated by dental occlusion. The latter receives input from the trigeminal nerve about proprioception of jaw muscles (_____ ______ nucleus), tactile information regarding food in the mouth (______ ______ nucleus), and pain information (_____ _____ nucleus). The _____ nerve then sends output to the MoM.
- closing
- opening
- trigeminal mesencephalic
- trigeminal main
- trigeminal spinal
- facial
The receptors for blinking reflexes in response to light are done in the _____. For noise, the receptors are in the _____. For sound attentuation, receptors are in the ____.
- retina
- cochlea
- cochlea
Afferents for reflexes:
- Blink to light: _____ nerve
- Blink to sound: _____ nucleus
- Sound attenuation: _____ nucleus
- optic
- cochlear
- cochlear
Presynaptic fibers for reflexes:
- Blink to light: _______ ______
- Blink to sound: _______ ______
- Sound attenuation: ______ ______ ______
- superior colliculus
- inferior colliculus
- superior olivary nucleus (pons)
Postsynaptic fibers for reflexes synapse a 2nd time:
- Blink to light: ______ nucleus
- Blink to sound: _______ nucleus
- Sound attenuation: ______ nucleus
- facial
- facial
- facial
Muscles used for CN VII related reflexes:
- Blink to light: _____ ______
- Blink to sound: _____ ______
- Sound attenuation: _________
- orbicularis oculi
- orbicularis oculi
- stapedius
Taste isn’t just due to taste bud information, but chemical stimulation of _______ receptors. Chemosensitive and somatosensory reception of food vapors on nerve endings of CN ___, ___, and ____ also help generate taste.
- olfactory
- V (trigeminal)
- IX (glossopharyngeal)
- X (vagus)
The average tongue has about ______ taste buds, but the number of papillae and taste buds is highly variable. This accounts for the vast differences of tastes amongst people.
5,000
Situated directly between the facial (CN VII) and vestibulocochlear nerves (CN VIII) where they project from the brainstem is the ______ ______.
nervus intermedius (intermediate nerve)
All sensory input for taste, regardless of initially ganglionic synapse, eventually goes to the facial nerve’s nucleus of the ______ ______.
solitary tract
1° gustatory afferents travel to the _______ tract to synapse. 2° fibers then either perform the ______ or _____ reflexes, or project uncrossed to the thalamus VPM, then the ______ cortex of the insula. This then projects to the orbitofrontal cortex with olfactory information, then to the amygdala, and finally to the _____ system.
- solitary
- swallowing
- salivation
- gustatory
- limbic
