Exam 4 Flashcards
Function of lateral cuneate nucleus
IL unconscious proprioception from upper extremity
Function of medial lemniscus
CL conscious proprioception from UE and LE (fibers cross to form the medial lemniscus)
What is in the level of sensory decussation of medulla
Lateral cuneate nucleus - unconscious proprioception from UE
Pyramids
Medial lemniscus - conscious proprioception from UE and LE
Function of medial longitudinal fasiculus
Axons of nerves (3,4,6) to eye muscles
Function of medial vestibular nucleus
Origin of medial vestibulospinal tract to innervate neck musculature
Function of inferior olivary nucleus
Relay stay between cortex and cerebellum and participate in allowing smooth coordinated movement
Parts of medulla at level of CN X/XII
Medial longitudinal fasiculus
Medial vestibular nucleus
Inferior olivary nucleus
Inferior cerebellar peduncle
Somatic Motor portion of vagus nerve
Innervates pharyngeal, laryngeal, and palate muscles
Cell bodies in nucleus ambiguus
Dysfunctions of somatic motor fibers of vagus nerve
Hoarseness - intrinsic of larynx
Dysphagia - palate and pharyngeal
Arch of soft palate droops on affected side and uvula deviates toward unaffected side
Visceral motor portion of vagus nerve
Causes decreased HR and contractility
Pre-ganglionic parasympathetic nerve cell bodies located in dorsal motor nucleus of the vagus and nucleus ambiguus
Visceral Sensory portion of vagus nerve
Baro and chemo receptors in aortic arch
Pathway for visceral sensory portion of vagus nerve
Baro and chemo receptors in aortic arch
Inferior ganglion of CN X
Central processes enter medualla and descend in tractus solitarius
Synapse on neurons in nucelus solitarius
Neurons send axons to cardiorespiratory centers in meduall and nucleus ambiguus (visceral motor portion of CN X)
Hypoglossal nerve supplies
Intrinsic muscles of tongue Genioglossal muscle (protrudes tongue and contralateral deviation of the tongue)
UMN Lesion to hypoglossal nerve
tongue deviates to opposite side of lesion due to unopposed pull of ipsilateral genioglossal muscles
LMN Lesion of hypoglossal nerve
Tongue deviates to ipsilateral side
Parts of medualla at level of CN VIII and IX
Lateral vestibular nucleus (lateral vestibulospinal tract) and vestibulocochelar nerve
Receptors for Vestibular nerve
Crista ampullaris and macula
function of Crista ampullaris (semicircular canals)
Detects angular acceleration of head (turning head)
Drives vestibular ocular reflex
Function of Macula
Detects position of head with respect to gravity (keeps head upright)
Important in maintaining balance
Detects linear acceleration of head
Location of crista ampullaris
Located in ampula
Location of macula
Located in utricle and saccule
Vestibular ocular reflex
Eyes reflexively turn opposite the direction of the head rotation
Vestibulospinal Reflex
Cause contraction of trunk musculature to maintain equilibrium
2 theories of BPPV
Canalithiasis - otoconia float freely in endolymph
Cupuloithiasis - otoconia attach to cupula
Causes of Meniere’s Syndrome
Defective circulationor reabsorption of endolymph fluid
4 signs of Meniere’s Syndrome
Aural fullness
Fluctuating hearing loss
Roraring tinnitis
Vertigo
Function of organ of corti
Converts acoustic energy into electrical energy
Primary auditory cortex
Superior surface of superior temporal lobe
Secondary cortical auditory areas
Wernicke’s area (adjacent to primary areas of superior temporal lobe)
Sensorineural hearing loss
Dysfunction of hair cells and/or vestibular nerve
Conductive hearing loss
Impairment of transmission of sound waves to the outer ear/tympanic membrane, middle ear/oval window (impacted auditory canal and fused ossicles)
Noise exposure hearing loss
Chronic intense sound exposure can cause damaged hair cells
Acoustic neuromas hearing loss
Schwannomas of the cochlear/vestibular nerve
Can also compress the facial nerve
Presbycusis hearing loss
Age related loss of hair cells
Ototoxicity
Antibiotics accumulate in inner ear can damage hair cells
