Auditory system & chemical senses Flashcards
5 qualities of taste
Bitterness, sourness, sweetness, saltiness, umami (savory)
Otosclerosis
Autosomal dominant genetic disorder characterized by fusion of the stapes to oval window causing difficulty of movement followed by eventual cessation of ear ossicle movement (most common adult cause of hearing loss)
Olfactory tract axons project directly to
Piriform cortex, amygdala, entorhinal cortex
Which part of the cochlea analyzes the quality of sounds?
Dorsal
Which part of the cochlea encodes intensity info?
Ventral
Destruction of the cochlea, cochlea nerve, or cochlea nuclei results in
Complete ipsilateral deafness
Gustatory pathway
CNs 7, 9, 10 => nucleus of the solitary tract in the medulla => ventral posteromedial nucleus of thalamus => primary gustatory cortex in anterior insula-frontal operculum => secondary gustatory cortex in orbitofrontal cortex
Anosmia
Loss or reduction of sense of smell, can be from problems at nasal, neuroepithelial, or central level
What 3 cranial nerves are involved in gustation?
7, 9, 10
Damage to the lateral lemniscus results in
Bilateral partial deafness, greatest in the contralateral ear
Organ of Corti
Auditory transductor, which consists of cells that bend in response to sound waves
Auditory sharpening
Processes whereby relay nuclei in the auditory pathways differentialy inhibit impulses concerned with certain frequencies thereby enhancing the frequencies of other sounds
Parcusis
Sound heard previously is heard repeatedly
Central auditory pathways are unlike any other ascending pathways due to what 2 factors
1) presence of accessory nuclei that modulate input 2) B representation of auditory impulses on each side
Release phenomenon
Elaborate auditory hallucination assoc. w/ sensorineural deafness or lesion of the pontine tegmentum
Dysosmia or parosmia
Distortions or illusions of smell
2-phase process of sound localization
1) convergence & comparison of auditory input from 2 ears 2) distribution of analysis to appropriate side of system
Olfactory hallucinations are most often due to seizures in the
Temporal lobe (uncinate fits)
Lesions of the auditory unimodal association areas result in
Auditory perceptual impairments, including cortical deafness, pure word deafness, auditory agnosia for sounds, phonagnosia
Auditory pathway
Cochlear nerve => dorsal (direct to lateral lemniscus) & ventral cochlea nucleus in medulla => B to superior olivary nucleus & trapezoid body => lateral lemniscus => inferior colliculus => MGN => Heschl’s gyrus
What structures are essential to sound localization?
Trapezoid body & superior olivary nucleus
Presbyacusis
Progressive loss of hearing with age
Self-audible bruits
Pulsating “whooshing” sounds associated with turbulent flow in AVM, carotid dissection, elevated ICP
The Primary Auditory Cortex is organized tonotopically, so that low frequencies are represented more
Anteriorly
Musical hallucinations are often caused by seizures in the
Right hemisphere
