Special Sense Organs Part 6 Flashcards
T/F: sound waves enter the external acoustic meatus, and the ossicles of the middle ear (malleus, incus, stapes) transmit the vibrations causing the tympanic membrane to vibrate which amplifies the vibration 1.2 times.
True
T/F: Because the oval window is much smaller in diameter than the tympanic membrane, the vibrations that enter the external acoustic meatus are amplified another 7 times.
False; actually another 17 times (in addition to the 1.2 times via the ossicles)
T/F: sound waves travel from the foot of stapes to the oval window to scala vestibuli to scala tympani to the round window to the basilar membrane which stimulates the spiral organ. This info is then transmitted to the cochlear nerve.
True
T/F: the vestibular labyrinth consists of two sacs, the saccule and the utricle, and three semicircular ducts. All of these structures contain perilymph.
False; they all contain endolymph
T/F: the saccule is larger than the utricle and communicates with all three semicircular ducts.
False; the utricle is larger and communicates with the semicircular ducts; the saccule communicates with the cochlear duct
How does the utricle communicate with the saccule?
via the utricosaccular duct
What are the hairlike sense organs within the utricle and saccule?
maculae
What are the maculae bathed in?
endolymph
What float on the endolymph bathing the maculae?
otoliths
T/F: Movements of the head cause the otoliths to deflect the maculae, eliciting impulses.
True
What type of accelerations are detected by the utricle? by the saccule?
utricle-centrifugal and vertical;
saccule- linear
What are the sense organs within the semicircular ducts called? Where are they located?
crista;
in the ampulla of each duct
T/F: semicircular ducts are not sensitve to accelerations in every direction.
False; they are sensitive to accelerations in every direction, but are particularly sensitive to rotational accelerations
Impulses initiated by sense organs in the vestibular labyrinth are carried by neurons with cell bodies located where?
in the vestibular ganglion
The dendrites carrying info to the vestibular ganglion from the sense organs in the vestibular labyrinth are collected into what two branches?
superior and inferior branch
Which branch carrying info to the vestibular ganglion from the sense organs is larger and carries info from the anterior and lateral semicircular ducts and the utricle? which branch carries info from the posterior semicircular duct and the saccule?
superior;
inferior
Axons from the vestibular ganglion make up what nerve?
vestibular nerve
What arteries provide blood supply to the labyrinth?
internal auditory artery (a branch of the basilar artery) and the stylomastoid artery (branch of the posterior auricular artery)
What plexuses provide sympathetics to the labyrinth?
cavernous and/or internal carotid plexuses
The cochlear nerve is compose of axons from cells in what ganglion?
spiral ganglion
Info from the cochlear nerve is relayed to what nuclei in the medulla oblongata?
olivary and trapezoid nuclei
From the olivary and trapezoid nuclei in the MO, info is carried in the lateral lemniscus to where?
inferior colliculi and/or medial geniculate bodies
From the inferior colliculi and/or medial geniculate bodies, where is info (originally from the cochlear nerve) relayed to?
temporal lobe, Brodman areas 41 and 42
The vestibular nerve is made up of axons from what ganglion?
vestibular ganglion
