auditory lec 4

Question 1

systems involved in balance? (4)

Answer 1

1. vestibular system
2. visual system
3. proprioceptive system
4. brain

Question 2

what are the 5 sensory organs of the inner ear?

Answer 2

• 3 semicircular canals
• 2 otolithic organs (utricle and saccule)

Question 3

diff bw semicircular CANAL vs DUCT?

Answer 3

• canal: boney
• duct: membranous

Question 4

where are the SCCs located in relation to the cochlea? (2)

Answer 4

posterior and superior

Question 5

which segment of temporal bone are the SCCs located in?

Answer 5

petrous

Question 6

what fluid is in the SCCs?

Answer 6

• endolymph (continuous w/ scala media)

Question 7

true or false: the anterior and posterior SCC are perpendicular to the lateral SCC

Answer 7

true

Question 8

what type of movement is each SCC sensitive to?

Answer 8

1. anterior SCC: vertical movements in saggital plane (nodding yes)
2. posterior SCC: vertical movements in coronal plane (bend to shoulders)
3. lateral SCC: horizontal movements in transverse plane (rotate head)

Question 9

T or F: the anterior SCC is approximately parallel to the gravitational plane during motion

Answer 9

false! lateral SCC*

Question 10

what is an ampulla?

Answer 10

the swelling at the end of each SCC

Question 11

what is the common crus? where does it terminate?

Answer 11

• common crus: where anterior and posterior SCCs come together
• terminates at vestibule

Question 12

what does the vestibule do?

Answer 12

connects SSC to cochlea

Question 13

what is in the vestibule? (2)

Answer 13

utricle and saccule

Question 14

what do the saccule and utricle contain? (2)

Answer 14

• otoconia
• sensory hair cells

Question 15

where specifically are the otoconia embedded? what do they do?

Answer 15

• embedded in macula
• inertia causes hair cell stimulation when head moves

Question 16

diff bw otoconia of saccule vs utricle?

Answer 16

• saccule: otoconia are in nearly vertical position. hair cells = in fluid and otoconia = on otolithic membrane.
• utricle: otoconia are in horizontal position and smaller than saccule ones.

Question 17

what are cristae?

Answer 17

folds in the inner membrane of AMPULLA (in SCCs, not utricle/saccule) containing hair cells.

Question 18

describe neural transmission of vestibular signals

Answer 18

• membrane movement moves cilia which triggers neural impulse
• transmitted to brain via cranial nerve 8 (VC nerve)

Question 19

what does pharyngeal pouch 1 give rise to? (2)

Answer 19

1. ET
2. middle ear cavity

Question 20

what does pharyngeal groove 1 give rise to? (1)

Answer 20

external auditory meatus

Question 21

what does what does pharyngeal arch 1 give rise to? (3)

Answer 21

• tensor tympani
• malleus
• incus

Question 22

what does pharyngeal arch 2 give rise to? (2)

Answer 22

• stapes
• stapedius

Question 23

which swellings form external ear?

Answer 23

• 6 swellings from arch 1 and 2

Question 24

where does the…
a) lining of middle ear
b) tympanic membrane
originate from?

Answer 24

a) first pouch
b) first pouch + groove

Question 25

T or F: Inner ear – does not develop from a pharyngeal arch, groove or pouch

Answer 25

true

Question 26

what does the inner ear develop from?

Answer 26

otic vesicle
(dorsal – utricle and SCC, ventral – saccule and scala media)