Test 2 - CENTRAL AUDITORY SYSTEM Flashcards
VIII cranial nerve (Auditory portion) is ______ neuron and is part of the ______________.
- 1st order
2. peripheral auditory system
Nerve fibers pass from the cochlea through the ___________.
Internal Auditory Canal
The Internal auditory canal begins at the ____________ and terminates at the _______________.
- cochlear modiolus
2. base of the brain
The fibers of the 8th nerve are innervated by the ______, ______, and the _____________
- Utricle
- Saccule
- Semicircular canals
[In the 8th nerve] There are approximately ________ nerve fibers in the cochlear portion and __________ in the vestibular portion.
- 30 Thousand
2. 20 Thousand
The auditory portion of the VIIIth nerve spirals through the _____________.
Internal Auditory Canal
The Internal Auditory Canal carries what 3 things?
- VIIIth Nerve
- VII Facial Nerve
- Internal Auditory Artery
The VIIIth nerve attaches to the brain at the__________.
cerebellopontine angle (CPA)
Ascending central auditory pathway involves these 5 nuclei:
- Cochlear nucleus
- Superior olivary complex
- Lateral lemniscus
- Inferior colliculus
- Medial geniculate body
From the cochlear nucleus there are two ascending pathways:
- Ipsilateral
2. Contralateral
______of fibers from Cochlear nucleus are Ipsilateral (remain on the same side) to ascend the ___________.
- 1/3
2. Superior olivary complex
_______ of fibers cross over/decussate the brainstem to the other _____________.
- 2/3
2. superior olivary complex
What are decussations?
crossover points in the brain that unite symmetrical portions of it’s two halves.
The first decussation in the auditory pathways occurs after the _________ at the level of the ___________.
- cochlear nucleus
2 trapezoid body
All neurons will synapse at the ___________ before going toward primary auditory cortex in the temporal lobe.
- medial geniculate body
_____________ are specialized nerve-fiber bundles that unite similar structures on both sides of the brain.
Commissures
The _____________ receives input from both the ipsilateral and contralateral cochlear nuclei.
Superior Olivary Complex
The _____________ provides a major pathway for the transmission of impulses from the ipsilateral lower brain stem.
Lateral Lemniscus
The ______________ receives afferent stimulation from both superior olivary complexes.
Inferior Colliculus
What is the Medial Geniculate Body?
The final subcortical auditory relay station, found in the thalamus on each side of the brain.
From the medial geniculate body neurons proceed to the ipsilateral temporal lobe via ______________.
Auditory Radiations
Ascending/afferent pathway terminates in the primary auditory cortex reception area: AKA
Heschel’s gyrus
The efferent pathway is comprised of what two main segments?
- Cortex and rostral Brainstem system
2. The Olivocochlear system
The Olivocochlear system
Made up of neurons which make up medial and lateral superior olivary complex nuclei on both sides of the brainstem.
Each nucleus along ascending pathway is ________ organized
tonotopically
Neurons in the primary auditory cortex also maintain a representation of the ___________.
tonotopic organization (frequency map) of the basilar membrane.
From the cochlear nuclei, small fibers connect with the __________ where the auditory message joins all other sensory messages.
reticular formation
The ____________ is where the auditory message joins all other sensory messages.
reticular formation
The main function of the reticular formation is…
To select the type of sensory message to be treated first.
Conscious perception requires the integrity of both the ______________ and the ______________.
- Central Auditory System (primary auditory)
2. Reticular Formation (secondary auditory)
