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Flashcards in Embryology of the Ear Deck (39)
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1
Q

cristae ampullaris

A

in the ampulla of each semicircular canal

2
Q

macula

A

one in the utricle and one in the saccule

3
Q

cochlear

A

numerous along the cochlear duct

4
Q

what is the thickening of ectoderm called during the fourth week of development

A

ecotderm

5
Q

the otic placode forms __________ and then _______

A

otic placode and vesicle

6
Q

_________gives rise to the membranous labyrinth

A

otic vesicle

7
Q

the otic vesicle forms what two structures

A

utricle and saccule

8
Q

the utricle forms

A

endolymphatic duct, utricle and semicircular canals

9
Q

the saccule forms

A

the saccule and cochlear duct

10
Q

the _____________ is related to the cochlear duct and is involved in hearing

A

spiral ganglion

11
Q

the ____________is involved in detection of movement of the head

A

vestibular ganglion

12
Q

the ganglia form from

A

neural crest cells

13
Q

the otic capsule helps also form what skull bone

A

petrous part of the temporal bone

14
Q

what is the space called within the otic capsule

A

perilymphatic space

15
Q

what is the fluid within the perilymphatic space called

A

perilymph

16
Q

_________can cause malformation of the cochlea and deafness

A

rubella infection

17
Q

what is the significance of the perilymphatic space and the cochlear duct

A

it is related to it twice (once above and once below)

18
Q

What are the two space of the perilymphatic space called

A

scala tympani and scala vestbuli

19
Q

what helps form the tympanic membrane

A

the first pharyngeal groove

20
Q

what is the pouch lined with

A

endoderm

21
Q

what is the groove lined with

A

ectoderm and mesenchyme

22
Q

what germ layers is the tynmpanic membrane derived from

A

ecto, endo, meso (all three!)

23
Q

the 1st pharyngeal pouch helps form

A

the middle ear which is continuous with the mastoid antrum and nasopharynx ia pharyngotympanic tube (auditory tube)

24
Q

what are the three middle ear ossicles

A

malleus, incus, and stapes

25
Q

malleus and incus are derived from

A

1st pharyngeal arch

26
Q

stapes is derived from

A

cartilage of the second arch

27
Q

tensor tympani m is attached to ________and is derived from ________arch

A

malleus; mesenchyme of first arch

28
Q

the tensor tympani is innervated by

A

CN V

29
Q

stapedius is innervated by

A

facial nerve

30
Q

external ear develps at the crossroads of

A

1st and 2nd pharyngeal arches

31
Q

what is anotonia

A

absence of an ear

32
Q

what is microtia

A

small ear

33
Q

auricular appendages

A

persistence of auricular hillocks

34
Q

what dis microtia result from

A

absence of auricular hillocks and is characterized by the absence of the auricle; this defect is associatied with other defects

35
Q

___________-are small depressions located anterior to the auricle

A

preauricular sinuses

36
Q

preauricular sinuses are the result from

A

abnormal closure of the first pharyngeal groove

37
Q

what happens when the plug of cells in front of the tynpanic membrane fail to regress

A

atresia of external auditory meatus occurs

38
Q

__________is when epidermoid tissue is within the tympanic membrane

A

congenital cholesteatome

39
Q

congenital fixation of the stapes

A

Complete absence of the annular ligament of the stapes without evidence of otosclerotic bone growth may be congenital stapes fixation.