Deck 18: Development of the Ears and Eyes

Question 1

Researchers have shown that the various regions of the developing eye are specified by different transcription factors whose expression is induced by the adjacent tissues.Which region of the eye requires the transcription factor Chx10?

A) Optic stalk
B) Neural retina
C) Pigmented retina
D) Lens
E) Cornea

Answer 1

B

Question 2

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

Answer 2

C

Question 3

Coloboma results from failure of which development event?

A) Eye induction
B) Differentiation of the photoreceptors
C) Regression of the hyaloid artery
D) Closure of the optic fissure
E) Formation of the eyelids

Answer 3

D

Question 4

Researchers have shown that the various regions of the developing eye are specified by different transcription factors whose expression is induced by the adjacent tissues.Chx10 is one such factor that is required for the development of the neural retina.What growth factor regulates its expression?

A) Shh
B) TgfBeta
C) Fgf
D) Egf
E) Vegf

Question 5

Which growth factor signaling pathway initiates retinal differentiation in the fovea?

A) Shh
B) Wnt
C) Notch
D) Bmp
E) Fgf

Question 6

The inner ear arises from which structure?

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

Question 7

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

A) Cristae
B) Organ of Corti
C) Maculae

Question 8

What are the key protein constituent(s) of the lens?

A) Melanin
B) Crystallins
C) Keratins

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

During retinal differentiation,the various cell types differentiate in sequence.Which cell type is the last to be born?

A) Müller
B) Ganglion
C) Amacrine
D) Bipolar
E) Rod
F) Cone

Question 11

Mutations in the gene encoding the FOXC2 transcription factor would be expected to cause which anomaly?

A) Epicanthal folds
B) Cryptophthalmos
C) Epibulbar dermoids
D) Distichiasis
E) Ocular telangiectasia

Question 12

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 13

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 14

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%

Question 15

Protanopes lack which cell type?

A) S cones
B) M cones
C) L cones
D) Rods

Question 16

The cristae detect which modality?

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

Question 17

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 18

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 19

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 20

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 21

Goldenhar syndrome is characterized by a spectrum of defects.What eye abnormality is the cardinal finding of this syndrome?

A) Epicanthal folds
B) Cryptophthalmos
C) Epibulbar dermoids
D) Distichiasis
E) Ocular telangiectasia

Question 22

Which is the most frequent genetic syndrome that affects the retina?

A) Osteoporosis-pseudoglioma syndrome
B) Leber congenital amaurosis syndrome
C) Retinitis pigmentosa
D) Familial exudative vitreoretinopathy
E) Norrie disease