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Flashcards in Sensory Systems Deck (10):

Where does CN VIII enter the brainstem? Where do fibers of the auditory pathway decussate?

Cerebellopontine angle. Decussates in Trapezoid Body.


What is the difference between conduction and sensorineural deafness?

Conduction: prevents sound from reaching Organ of Corti. Ex) obstruction, otitis medius, defect in middle/external ear
Sensorineural: disease of the cochlea/ nerve


What are the Weber and Rinne hearing tests?

Weber: Tuning fork at top of skull--> should hear equally in both ears.

Rinne: Vibrating tuning fork on mastoid process, then when in front of hear--> Air conduction > bone conduction.


Describe the results of Weber and Rinne test in Conduction and Sensorineural deafness

Conduction: Weber (louder on affected side). Abnormal Rinne test.
Sensorineural: Weber (louder on unaffected side). Normal Rinne test.


Which sensory modality is NOT relayed to the thalamus?



What can Vit. B1 (Thiamine) intoxication lead cause?

Strachan Syndrome: sensorineural deafness, optic atrophy, and spinal ataxia.


What is Kallman Syndrome (lack of formation of oflactory tract)?

Hypothalamic neurons rely on olfactory tract to migrate to destinations. GnRH neurons do not migrate.
Symptoms: anosmia, hypogonadism, and infertility


Which nucleus does taste travel to? From which cranial nerves?

Solitary Nucleus.
CN VII (anterior 2/3 tongue) and IX (posterior 1/3 tongue)


What is a common finding in Neurofibromatosis Type 2?

Bilateral acoustic neuroma. Rinne test is normal. Weber test may be normal is both ears affected equally.


Describe the Pacinian and Meissner and Merkel corpuscles.

Pacinian: coarse spatial differences. Deep pressure, vibration, skin stretch.
Meissner/Merkel: fine spacial differences. Light touch, pressure.