Devt Of The Ear

Question 1

For the inner ear

Otic placode is developed during week

Answer 1

3

Question 2

After otic placode, which structure is developed? At what week?

Answer 2

Otic vesicle/ auditory vesicle

Week 4

Question 3

Ventral portions if otic vesicle

Answer 3

Saccule

Cochlear duct

Question 4

Dorsal portions if otic vesicle

Answer 4

Utricle
Semicircular canals
Endolymphatic duct

Question 5

At what week does the cochlear duct start to develop

Answer 5

6

Question 6

Tubular outgrowths from lower pole of saccule

Answer 6

Cochlear duct

Question 7

Which structure forms the organ of corti?

Answer 7

Cochlear duct?

Question 8

Which drugs cause congential deafness?

Answer 8

Streptomycin

Quanine

Question 9

Diseases that cause congenital deafness

Answer 9

Rubella
Taxoplasmosia
Erythroblastosisfetalis
DM
Hyperthyroidism

Question 10

Sensory cells of organ of corti

Saccule (ventral)

Utricle (dorsal)

Are derived from

Answer 10

Neural crest and wall of otic vesicle

Question 11

What do the neural crest and wall of otic vesicle form

Answer 11

Statoacoustic gangliob

Question 12

Tympanic cavity is derived from

Answer 12

1st pharyngeal pouch - Distal part

Question 13

Which is derived from the proximal portion of the 1st pharyngeal pouch?

Answer 13

Eustachian tube

Question 14

The ossicles are derived from

Answer 14

1st Pharyngeal Arch (Malleus, Incus)

2nd Pharyngeal Arch (Stapes)

Question 15

The External Auditory Meatus is derived from

Answer 15

1st Pharyngeal Cleft

so may Pharyngeal cleft, pouch and arch

Question 16

Auricle is developed from

Answer 16

6 mesenchymal proliferations (auricular hillocks surrounding 1st pharyngeal clefts)

Question 17

Initial location of auricle

Answer 17

Lower neck

Question 18

Why does the auricle ascend at the level of the eyes

Answer 18

Due to development of the mandible :o

Question 19

Abnormal auricular shape may mean

Answer 19

Trisomy 18, 21

Question 20

Meatal plug develops at the bottom of the meatus at the _________ month and dissolves at the __________ month of life

Answer 20

3rd

7th