auditory lec 4 Flashcards
systems involved in balance? (4)
- vestibular system
- visual system
- proprioceptive system
- brain
what are the 5 sensory organs of the inner ear?
- 3 semicircular canals
- 2 otolithic organs (utricle and saccule)
diff bw semicircular CANAL vs DUCT?
- canal: boney
- duct: membranous
where are the SCCs located in relation to the cochlea? (2)
posterior and superior
which segment of temporal bone are the SCCs located in?
petrous
what fluid is in the SCCs?
- endolymph (continuous w/ scala media)
true or false: the anterior and posterior SCC are perpendicular to the lateral SCC
true
what type of movement is each SCC sensitive to?
- anterior SCC: vertical movements in saggital plane (nodding yes)
- posterior SCC: vertical movements in coronal plane (bend to shoulders)
- lateral SCC: horizontal movements in transverse plane (rotate head)
T or F: the anterior SCC is approximately parallel to the gravitational plane during motion
false! lateral SCC*
what is an ampulla?
the swelling at the end of each SCC
what is the common crus? where does it terminate?
- common crus: where anterior and posterior SCCs come together
- terminates at vestibule
what does the vestibule do?
connects SSC to cochlea
what is in the vestibule? (2)
utricle and saccule
what do the saccule and utricle contain? (2)
- otoconia
- sensory hair cells
where specifically are the otoconia embedded? what do they do?
- embedded in macula
- inertia causes hair cell stimulation when head moves
diff bw otoconia of saccule vs utricle?
- 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.
what are cristae?
folds in the inner membrane of AMPULLA (in SCCs, not utricle/saccule) containing hair cells.
describe neural transmission of vestibular signals
- membrane movement moves cilia which triggers neural impulse
- transmitted to brain via cranial nerve 8 (VC nerve)
what does pharyngeal pouch 1 give rise to? (2)
- ET
- middle ear cavity
what does pharyngeal groove 1 give rise to? (1)
external auditory meatus
what does what does pharyngeal arch 1 give rise to? (3)
- tensor tympani
- malleus
- incus
what does pharyngeal arch 2 give rise to? (2)
- stapes
- stapedius
which swellings form external ear?
- 6 swellings from arch 1 and 2
where does the…
a) lining of middle ear
b) tympanic membrane
originate from?
a) first pouch
b) first pouch + groove
T or F: Inner ear – does not develop from a pharyngeal arch, groove or pouch
true
what does the inner ear develop from?
otic vesicle
(dorsal – utricle and SCC, ventral – saccule and scala media)
