Deck 19: Development of the Ears

Question 1

The inner ear arises from which structure?

A) First pharyngeal pouch
B) First pharyngeal cleft
C) Otic placode
D) Hindbrain

Answer 1

C

Question 2

Microtia/anotia can be associated with other birth defects as a component of a syndrome.What percentage of children with microtia/anotia would be expected to have additional congenital abnormalities?

A) 5%-10%
B) 10%-20%
C) 20%-40%
D) 50%-80%
E) Essentially 100%

Answer 2

C

Question 3

The prosensory region in the saccule forms which structure(s)?

A) Cristae
B) Organ of Corti
C) Maculae

Answer 3

C

Question 4

The number of hair and supporting cells in the inner ear is determined by which signaling pathway?

A) Planar polarity pathway
B) Wnt canonical pathway
C) Notch lateral inhibition pathway
D) Fgf signaling
E) Shh signaling

Question 5

Branchio-oto-renal syndrome,characterized by kidney and hearing defects,is due to mutation of which gene?

A) EYES ABSENT HOMOLOG 1(EYA1)
B) EYES ABSENT HOMOLOG 4 (EYA4)
C) POU4F3
D) CONNEXIN 26
E) FGF8

Question 6

Which signaling pathway controls the orientation and arrangement of the stereocilia on the inner hair cells?

A) Wnt canonical
B) Planar polarity
C) Fgf
D) Bmp
E) Hedgehog

Question 7

Hereditary deafness can result from mutations in many genes.Which gene is mutated most frequently in nonsyndromic congenital deafness?

A) CONNEXIN 26
B) MYO7A
C) CADHERIN 23
D) HARMONIN
E) PROTOCADHERIN 15

Question 8

The cristae detect which modality?

A) Sound vibrations
B) Gravity
C) Linear acceleration
D) Angular acceleration

Question 9

Which muscle(s)are associated with the ear ossicles?

A) Tensor tympani and stapedius
B) Stylopharyngeus
C) Stylohyoid
D) Lateral pterygoid

Question 10

Development of the sensory regions of the inner ear involves the formation of hair cells and supporting cells by the process of lateral inhibition controlled by Notch signaling.How would overexpression of the transcription factors Hes1 and 5,which are modulated by Notch signaling,be expected to affect the number of hair cells or supporting cells?

A) The overall number of supporting cells would increase.
B) The overall number of supporting cells would decrease.
C) The overall number of hair cells would increase.
D) The overall number of hair cells would decrease.
E) No change would occur in the number of hair cells or supporting cells.

Question 11

Would mutation in genes that encode cytoskeletal components such as ACTIN,ESPSIN,and HARMONIN be expected to result in sensorineural or conductive hearing loss?

A) Sensorineural
B) Conductive

Question 12

Researchers have genetically inactivated transcription factors that are expressed in the developing ear of mice.This has shown that various transcription factors are necessary for the development of different regions of the inner ear.Pax2 function is required for development of which region of the inner ear?

A) Lateral canal
B) Anterior and posterior canals
C) Cochlea
D) Utricle
E) Endolymphatic duct and sac