Flashcards in Unit VIII - Ear Pt. 2 Deck (70)
What is the purpose of the numerous hair-like projections that project superiorward from the basilar/spiral membrane of the spiral organ?
They are sensitive to frequency and amplitude of sound waves that enter the cochlea
What covers the hair cells seen in the spiral organ?
Where are the cell bodies located for the primary sensory neurons of the spiral organ that receive information from the receptor cells?
When sound waves enter the external acoustic meatus, what structure vibrates?
What structures transmit the vibrations from the tympanic membrane?
Ossicles of the middle ear (malleus, incus, and stapes, in that order)
What process amplifies the vibrations 1.2 times?
Transmission of vibrations through middle ear ossicles
What is the reason that vibrations that enter the external acoustic meatus are amplified another 17 times?
The oval window diameter is much smaller than the tympanic membrane
The foot of which ossicle articulates with the oval window?
What forms the base of the scala vestibuli?
After the vibrations are transmitted through the ossicles, where are they then transmitted?
Through the perilymph of the scala vestibuli and the scala tympani, eventually reaching the round window
After the vibrations are transmitted through the perilymph, what structure vibrates, and what is the result?
Basilar membrane; stimulation of receptors in the spiral organ
After the receptors in the spiral organ are stimulated, where is the information then transmitted?
To the cochlear nerve
What fluid is contained in the saccule, utricle, and three semicircular ducts?
What are the three semicircular ducts?
Anterior, lateral, posterior
What does the saccule communicate with?
Which is larger: saccule or utricle?
What does the utricle communicate with?
All three semicircular ducts and the saccule
How does the utricle communicate with the saccule?
What are the sense organs within the utricle and saccule?
Hairlike projections called maculae
What bathes the maculae?
What tiny structures float on the endolymph that bathes the maculae?
What kind of action causes the otoliths to deflect the maculae and thus elicit impulses?
Movements of the head
Which detects centrifugal and linear in any direction accelerations: utricle or saccule?
Which detects linear accelerations: utricle or saccule?
What are the sense organs located within the semicircular ducts?
Where are the crista located in the semicircular ducts?
In the ampulla of each duct
What movements are the semicircular ducts sensitive to?
Accelerations in any direction, but particularly sensitive to rotational accelerations
Where are the cell bodies located for the neurons that carry information from the impulses that are initiated by the sense organs of the vestibular labyrinth (maculae and crista)?
What are the two branches in which the dendrites carrying information to the vestibular ganglion are collected in?
Superior and inferior branch