Cranial nerve dysfunction Flashcards
CN I (olfactory)
sensory. for smell
CN II (optic)
sensory. For vision. afferents for pupillary and accommodation reflex
pupillary reflex
the pupillary light reflex (PLR) is the constriction of the pupil that is elicited by an increase in illumination of the retina.
Accommodation reflex
The accommodation reflex (or near response) is a three-part reflex that brings near objects into focus through lens thickening, pupillary constriction, and inward rotation of the eye
CN III (oculomotor)
Motor and autonomic. moves eyes up, down, medially and raises upper eyelid. efferents for accommodation reflex, pupillary reflex and vestibuloocular reflex.
Constricts the pupils
vestibulo-ocular reflex
The vestibulo-ocular reflex is a reflex acting to stabilize gaze during head movement, with eye movement due to activation of the vestibular system.
CN IV (trochlear)
motor. moves eye medially and down. efferents for vestibulo-ocular reflex
CN V (trigeminal)
sensory and motor. Somatosensory for face. muscles of mastication. afferents for the corneal reflex
Corneal reflex
The corneal reflex, also known as the blink reflex or eyelid reflex, is an involuntary blinking of the eyelids elicited by stimulation of the cornea
CN VI (abducens)
motor. moves eye laterally. efferents for vestibulo-ocular reflex
CN VII (facial)
motor, autonomic and sensory. tears and salvation, anterior 2/3 of tongue for taste, muscles of facial expression. efferents for corneal reflex
CN VIII (vesibulocochlear)
sensory. hearing. sensation of head position relative to head movements. afferent for vestibulo-ocular reflex
CN IX (glossopharyngeal)
sensory, motor and autonomic. posterior 1/3 of tongue for taste. salvation. constricts pharynx. afferents for gag and swallowing reflex
gag reflex
The gag reflex, also known as the pharyngeal reflex or laryngeal spasm, is a contraction of the back of the throat triggered by an object touching the roof of your mouth, the back of your tongue, the area around your tonsils, or the back of your throat.
swallowing reflex
The swallowing reflex produces sequential activation of the tongue, pharyngeal and laryngeal muscles to propel the food bolus from the oral cavity to the esophagus without aspiration of food into the airways
CN X (vagus)
sensory, motor and autonomic. sensation from pharynx, larynx and external auditory meatus. regulates swallowing and efferents for swallowing and gag reflex. autonomics for heart.
CN XI (accessory)
motor. elevates shoulder and turns head.
CN XII (hypoglossal)
motor. moves tongue
CN III innervates
levator palpebrae superioris, the superior rectus muscle, the inferior rectus muscle, the medial rectus muscle, the inferior oblique muscle
CN IV innervates
superior oblique muscle
CN VI innervates
lateral rectus muscle
Consensual reflex
Constriction of the pupil in the other eye
CN V innervates
temporalis, masseter and pterygoid muscles
CN VII innervates
frontalis, orbicularis oculi, buccinator, orbicularis oris, platysma, the posterior belly of the digastric, and the stapedius muscle
geniculate ganglion
The geniculate ganglion is a sensory ganglion of the facial nerve (CN VII). It contains the cell bodies of the fibers responsible for conducting taste sensation from the anterior two-thirds of the tongue
chorda tympani
nerve that supplies the anterior 2/3 of the tongue for taste
greater Petrosal nerve
nerve that makes me cry lul
corticobrainstem tract for upper face muscles
tracts provide bilateral signals to the region of the facial nucleus that innervates the muscles in the upper face.
both the right and left motor cortex send signals to the right facial nerve nucleus that activate the facial nerve to close the right eye.
corticobrainstem tract for lower face muscles
Corticobrainstem tracts send contralateral signals to the region of the facial nucleus that innervates muscles of the lower face.
the left motor cortex sends signals to the right facial nerve nucleus, and the right facial nerve signals muscles that move the right side of the lips
A corticobrainstem tract lesion affecting the L side of brain
Because the contralateral cortex controls the muscles of the lower face, the person is unable to generate a smile on the right side.
the upper face is innervated bilaterally, the person with this corticobrainstem tract lesion can close both eyes.
Bells palsy
Difficulty with eye closure can damage cornea
Idiopathic or viral onset
May involve hearing: stapedius mm
Primary auditory cortex
Conscious awareness of the intensity of sounds
Auditory association cortex
Compares sounds with memories of other sounds, then categorizes the sounds as language, music, or noise
Wernicke’s area
Comprehension of spoken language
CN IX innervation
Stylopharyngeus muscle. the muscle that helps you gag lol
CN X innervation
muscles of the soft palate, pharynx, and larynx which are associated with speech and swallowing
CN XI innervation
trapezius and sternocleidomastoid
Dysphagia
Dysphagia is difficulty with swallowing.
Frequent choking, lack of awareness of food in one side of the mouth, or food coming out of the nose may indicate dysfunctions of CNs 5, 7, 9, 10, or 12.
Dysarthria
Dysarthria is poor control of the speech muscles.
Only vocal speech is affected; people with dysarthria can understand the spoken language and can write and read.
Causes of dysarthria
Motor neuron involvement of CNs 5, 7, 10, or 12
Motor tract neuron lesions or muscle dysfunction
what CNs make up the blink reflex?
CN V and CN VII. CN V for afferent part and CN VII for efferent part
