Auditory System Flashcards
General overview of the auditory pathway.
hair cell
cochlear nerve
superior olivary nucleus
lateral lemniscus, inferior colliculus, medial geniculate body and primary auditory cortex
Hair cells are innervated by the peripheral process of bipolar neurons whose cell bodies from the ______ ______
spiral ganglion, which is embedded in the modiolus
Where does the cochlear nerve terminate?
the Cochlear Nuclei
on the postero-lateral aspect of the upper medulla the cochleard nerve passes over the inferior cerebellar peduncle and terminates on neurons in the dorsal and ventral cochlear nucleus
The ______ _______ is the topographical location of the dorsal cochlear nuclues
acoustic tubercle: axons from these neurons form the dorsalm intermediate, and ventral acoustic stria
Describe the dorsal and intermediate Acoustic Striae.
the dorsal stria may be topographically visible as the stria medullaris acoustica
both dorsal and intermeidate decussate in the upper medualla and ascend in the contralateral lateral lemniscus
Where does the lateral lemniscus terminate?
upon neurons in the inferior colliculus
Describe the Ventral Acoustic Stria
as the ventral stria crosse the medial lemniscus they form the trapezoid body
these fibers terminate bilaterally in the superior olivary nucleus (SON).
The Superior olivary nucleus (SON) projects fibers to the _______ _______ primarily through the ipsilateral _______ _______
inferior colliculus
lateral lemniscus
Describe the relationship between the inferior colliculus and medial geniculate body?
fibers from the inferior colliculus project to the medial geniculate body via the brachium of the inferior colliculus
Describe the relationship between the medial geniculate body and the primary auditory cortex?
fibers from the medial geniculate body project to the primary auditory cortex via the sublenticular (auditory) radiations.
Describe relationship within the auditory cortices.
Primary auditory cortex is located in the transverse and superior temporal gyri
auditory association cortex for the processing and integration of sounds is located in the PTO association cortex and Wernick’s area
the superior longitudinal fasciculus directly links the auditory association area to Broca’s speech area
The medial superior olivary nucleus is important in ______ _______?
localizing sounds
Neurons in the _______ ____ ___ _____ gives rise to mist of the olivocochlead efferents, which exert inhibitory influences upon hair cells of the organ of corti.
lateral superior olivary nucleus
peripherally, these fiber pass through the vestibular division and cross over to the cochlear division via the vestibulocochlear anastomosis
How does a unilateral lesion of the cochlear nerve present?
ipsilateral complete deafness
How does a unilateral lesion of the central auditory pathway present?
bilateral diminution of hearing which is more prominent in the contralateral ear
structures affected include: lateral lemniscus, inferior colliculus and brachium, and the medial geniculate body
