Special Sense Organs Part 6

Question 1

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.

Answer 1

True

Question 2

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.

Answer 2

False; actually another 17 times (in addition to the 1.2 times via the ossicles)

Question 3

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.

Answer 3

True

Question 4

T/F: the vestibular labyrinth consists of two sacs, the saccule and the utricle, and three semicircular ducts. All of these structures contain perilymph.

Answer 4

False; they all contain endolymph

Question 5

T/F: the saccule is larger than the utricle and communicates with all three semicircular ducts.

Answer 5

False; the utricle is larger and communicates with the semicircular ducts; the saccule communicates with the cochlear duct

Question 6

How does the utricle communicate with the saccule?

Answer 6

via the utricosaccular duct

Question 7

What are the hairlike sense organs within the utricle and saccule?

Answer 7

maculae

Question 8

What are the maculae bathed in?

Answer 8

endolymph

Question 9

What float on the endolymph bathing the maculae?

Answer 9

otoliths

Question 10

T/F: Movements of the head cause the otoliths to deflect the maculae, eliciting impulses.

Answer 10

True

Question 11

What type of accelerations are detected by the utricle? by the saccule?

Answer 11

utricle-centrifugal and vertical;

saccule- linear

Question 12

What are the sense organs within the semicircular ducts called? Where are they located?

Answer 12

crista;

in the ampulla of each duct

Question 13

T/F: semicircular ducts are not sensitve to accelerations in every direction.

Answer 13

False; they are sensitive to accelerations in every direction, but are particularly sensitive to rotational accelerations

Question 14

Impulses initiated by sense organs in the vestibular labyrinth are carried by neurons with cell bodies located where?

Answer 14

in the vestibular ganglion

Question 15

The dendrites carrying info to the vestibular ganglion from the sense organs in the vestibular labyrinth are collected into what two branches?

Answer 15

superior and inferior branch

Question 16

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?

Answer 16

superior;

inferior

Question 17

Axons from the vestibular ganglion make up what nerve?

Answer 17

vestibular nerve

Question 18

What arteries provide blood supply to the labyrinth?

Answer 18

internal auditory artery (a branch of the basilar artery) and the stylomastoid artery (branch of the posterior auricular artery)

Question 19

What plexuses provide sympathetics to the labyrinth?

Answer 19

cavernous and/or internal carotid plexuses

Question 20

The cochlear nerve is compose of axons from cells in what ganglion?

Answer 20

spiral ganglion

Question 21

Info from the cochlear nerve is relayed to what nuclei in the medulla oblongata?

Answer 21

olivary and trapezoid nuclei

Question 22

From the olivary and trapezoid nuclei in the MO, info is carried in the lateral lemniscus to where?

Answer 22

inferior colliculi and/or medial geniculate bodies

Question 23

From the inferior colliculi and/or medial geniculate bodies, where is info (originally from the cochlear nerve) relayed to?

Answer 23

temporal lobe, Brodman areas 41 and 42

Question 24

The vestibular nerve is made up of axons from what ganglion?

Answer 24

vestibular ganglion

Question 25

From the vestibular ganglion, where are axons carried?

Answer 25

to the vestibular nuclear complex of the MO

Question 26

From the vestibular nuclear complex, where is info carried?

Answer 26

to the cerebellum where it is processed.

Question 27

The?

Answer 27

End.