Ear Development Flashcards

1
Q

What is the critical period for ear developement?

A. Week 4-6

B. Week 4-7

C. Week 4-8

D. Week 4-9

A

Week 4 - 8

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2
Q

The auricle of the ear is derived from what 2 pharyngeal arches?

What is the cellular origin of the auricular hillocks?

A

Arches 1 and 2

Neural crest covered

NOTE: Auricular hillocks are mesenchymal swellings covered with ectoderm

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3
Q

What is the innervation of the ear? (4)

A

Great Auricular

Auriculotemporal N (V3)

Facial N

Auricular Branches off Vagun N.

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4
Q

How do we get the external shape of the ear?

A

The 6 auricular hillocks migrate to form the ear

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5
Q

How do we end up with abborrent auricular skin tags?

A. Abnormal proliferation and migration of neural crest cells

B. Abnormal migration of the surface ectoderm from groove of arch 1

C. Abrornmal migration of neural crest cells

D. None of the above

A

Abnormal migration of the surface ectoderm from groove of arch 1

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6
Q

How do we end up with abborent auricular tags that contain cartilage?

A. Abnormal proliferation and migration of neural crest cells

B. Abnormal migration of the surface ectoderm from groove of arch 1

C. Abrornmal migration of neural crest cells

D. None of the above

A

Abrornmal migration of neural crest cells

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7
Q

How does Anotia occur, where no ear develops?

A. Abnormal proliferation and migration of neural crest cells

B. Abnormal migration of the surface ectoderm from groove of arch 1

C. Abrornmal migration of neural crest cells

D. None of the above

A

Abnormal proliferation and migration of neural crest cells

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8
Q

How does Microtia, the presentation of a small ear?

A

Abnormal migration of the neural crest cells

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9
Q

The external auditory meatus is derived from what structure?

A. Pharyngeal Arch 1

B. Pharyngeal Arch 2

C. Pharyngeal Pouch 1

D. Pharyngeal groove 1

A

Pharyngeal Pouch 1

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10
Q

To form the external auditory meatus we need apopotosis of what structure?

A. PA 1

B. Meatal Plug

C. Beetle Plug

D. Phayrngeal Groove 1

A

Meatal plug

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11
Q

Which of the following parts of the ear is the first to form and is derived from surface ectoderm?

A. External Ear

B. Middle Ear

C. Inner Ear

A

Inner Ear

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12
Q

The development of the inner ear starts at week 4. Along the rhombencephalon we begin to thicken the surface ectoderm on the external side and form what structure?

A. Otic Placode

B. Otic Pit

C. Otic Vesicle

A

Otic Placode

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13
Q

The invagination of the otic placode form the _______, and once that structure rounds up we form the ________. These structures all give rise to the Primordium of Membranous Labryinth.

A

The invagination of the otic placode form the otic pit, and once that structure rounds up we form the otic vesicle. These structures all give rise to the Primordium of Membranous Labryinth.

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14
Q

The membranous labrynth comes from surface ectoderm and gives rise to two major structures. One comes from the dorsal portion, and one comes from the ventral portion. What are these structures?

A

ventral: Saccule
dorsal: Utricle

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15
Q

All of the following come from the dorsal portion of teh membranous labyrinth, EXCEPT which of the following that comes from the ventral portion?

A. Macula of Utricle

B. Endolymphatic Duct

C. Organ of Corti

D. Semicircular Ducts and Ampullae

A

Organ of Corti

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16
Q

Name 4 structures that come from the ventral portion of the membranous labyrinth?

A

Cochlear Duct

Ductus reunions

Macula of Saccule

Organ of Corti

17
Q

The very bottom portion of the membranous labyrinth begins to spiral and forms which of the following strucutres?

A. Maculae of Saccule

B. Organ of Corti

C. Cochlear Duct

D. None of the above

A

Cochlear Duct

18
Q

Which of the following strctures connects the saccule to the cochlear duct?

A. Utricle

B. Ductus Reunions

C. Ampullae

A

Ductus Reunions

19
Q

Name the 4 strucutures within the inner ear where hair cells can be found.

A

Maculae of Saccule

Maculae of Utricle

Ampulla

Organ of Corti

20
Q

Hair cells in specific locations of the inner ear have different functions. The hair cells in which location provides acceleration or rotational movement?

A. Ampullae of semicircular canal

B. Macula

C. Organ of Corti

A

Ampullae

21
Q

T/F: all of the hair cells of the ear come from surface ectoderm

A

True

22
Q

Cranial N. 8 comes from which of the following cell origins?

A. Surface ectoderm

B. Neuroectoderm

C. Neural crest cells

D. Mesenchyme

A

Surface ectoderm

23
Q

Which of the following is true of the perilymph and NOT the endolymph?

A. High K and protein, and low sodium

B. Smilar concentration to CSF

C. Produced by the stria vascularis

D. All of the above are true of both

A

Smilar concentration to CSF

  • high sodium, low potassium
24
Q

What fills the structures of the membranous labyrinth?

A. Perilymph

B. CSF

C. Endolymph

D. All of the above

A

Endolymph

25
Q

T/F: Anything from the perilymph can go out into the subarachnoid space and this can lead to issues with infections in the bony labyrinth

A

True

26
Q

What is the cell origin of the membranous labyrinth?

A. Surface ectoderm

B. Neuroectoderm

C. Mesenchyme

D. None

A

Mesenchyme

27
Q

All of the following spaces are filled with perilymph, except for which of the following that is filled with endolymph?

A. Scala Vestibuli

B. Scala Media

C. Scala Tympani

A

Scala media

28
Q

Which of the following structures is derived from ectoderm, mesoderm and endoderm?

A. Scala vestibuli

B. Bony labyrinth

C. Malleus and Incus

D. Tympanic Membrane

A

Tympanic Membrane

29
Q

T/F: Ossicles are covered with ectodermal epithelium

A

False; ENDOdermal epithelium

30
Q

Which of the following forms the tubotympanic recess?

A. 1st PA

B. 1st Pharyngeal goove (cleft)

C. 1st Pharyngeal pouch

D. None of the above

A

1st Pharyngeal Pouch

31
Q

The malleus, incus, and stapes differ when it comes to pharyngeal arch derivation, but agree when it comes to cellular origin. What is their shared cell origin?

What are those 3 ossicles covered by?

A

Neural crest cell

Endodermal epithelium

32
Q

The Tensor Tympani (PA 1) and Stapedius (PA 2) both prevent damage from loud noises.

A

1

33
Q

Rubella infection during which of the following weeks can cause defects of the spiral organ and deafness?

A. Week 4-8

B. Week 6-8

C. Week 7-8

D. Week 4

A

Week 7-8

34
Q

Which of the following is the leading cause of congenital sensorineural hearing loss?

A. Rubella infection

B. Cytomegalovirus

C. Zika

D. Syphilis

A

Cytomegalovirus

35
Q

T/F: Congenital fixation of teh stapes can be caused by issues of the 2nd PA, which affects the sound conduction apparatus of middle and external ear

A

True