Chapter 12 Flashcards
(12 cards)
In general, what areas/structures make up the ear related to it function?
the external ear
the middle ear/tympanic cavity
the internal ear
What does the trigeminal nerve (CN V) innervate in the middle ear?
the tensor tympani muscle which is attached to the malleus.
What is the function of the malleus?
vibrations from the tympanic membrane are transfer to the malleus, the malleus then sends vibration to the incus and stapes to the internal ear.
What is the function of the tympani muscle?
the tensor tympani muscle dampens low tones by pulling malleus internally increasing tension in the tympanic membrane
What does the facial nerve (CN VII) innervate in the middle ear?
the stapedius muscle
What is the function of the stapes?
it receives vibrations from the other auditory ossicles, malleus and incus, and transfers the vibration to the internal ear.
What is the function of the stapedius muscle?
it decreases sound intensity by pulling stapes away from the opening into the internal ear
What is tonic localization?
high tones are located more posteriormedially
low tones are located more anteriolaterally
1st order (or primary) neurons of auditory pathway originate where?
located in CN VIII gaglion (cochlear nuclei), they ar bilateral and synapse on hair cells
2nd order neurons of auditory pathway originate where?
at cochlear nuclei (dorsal/ventral)
3rd order neurons of auditory pathway originate where?
ascend from inferior colliculus
4th order neurons of auditory pathway originate where?
ascend as auditory radiation
