1 - Anatomy & Physiology of the Auditory Nervous System Flashcards
Afferent Fibers
Go from the inner ear to the nervous system
Cochlea is innervated by both ________ and ________.
Afferent Fibers
Efferent Fibers
Efferent Fibers
Go from the nervous system the the inner ear
What are the two types of afferent fibers?
Type I
Type II
Do afferent fibers have a myelin sheath?
No, not within the organ of corti
How are afferent fibers arranged?
Tonotopically
The lower frequencies are in the middle of the bundle, the higher frequencies are on the outside
What are Type I fibers also called?
Radial Fibers
What percentage of afferent fibers are Radial/Type I Fibers?
85%
How many hair cells do Type I/Radial Fibers connect to?
Only 1 or 2
How many Radial/Type I fibers innervate each inner hair cell?
Up to 20
What are Type II Fibers also called?
Outer Spiral Fibers
Which row of outer hair cells do Type II/Outer Spiral Fibers innervate?
The first row
How many outer hair cells do each Type II/Outer Spiral Fiber innervate?
A whole lot
Where do afferent fibers leave the cochlea?
Habenula Perforata
Which cranial nerve carries information from both the hearing and balance systems?
The VIIIth Cranial Nerve
Where is the habenula perforata located?
It is a small opening in the spiral laminia
When do the auditory nerves become mylenated?
Once they pass through the habenula perforata
Where is the first synapse for all auditory nerve fibers?
The Cochlear Nucleus
How is the cochlear nucleus arranged?
Tonotopically
Where do the auditory nerves synapse after the cochlear nucleus?
The olivary complex
The olivary complex is the first point in the nervous system where ________.
The two ears communicated with each other
What does the olivary complex allow for?
Sound Localization
Figure-Ground Separation
Binaural
Both ears
Figure-Ground Separation
Separating the signal from noise
Where does the inferior colliculus receive input?
From both the cochlear nucleus and the olivary complex
What might the olivary complex be the source for?
Central auditory processing deficits
When nerves leave the superior olive, where do they synapse next?
Lateral Lemniscus
Lemniscus
Ribbon
When nerves leave the lateral lemniscus, where do they synapse next?
Medial Geniculate
Geniculate
Knee-shaped
When nerves leave the medial geniculate, where do they next synapse?
(5)
Appropriate cortex areas
Herschel’s Area
Wernicke’s Area
Cerebellum
Reticular Formation
What does the reticular formation deal with?
Arousal
