Ear Embryology - ACht

Question 1

The ear structures form from which embryological division?

Answer 1

Rhombencephalon

Question 2

The bony labrynth is formed from mesenchyme that is inducted by?

Answer 2

The otic vesicle

Question 3

What do the malleus, incas, and stapes develope from?

Answer 3

Malleus and incus from dorsal tip of Meckel’s cartilage/first arch

Stapes from Reichert’s cartilage/second arch

Question 4

What does the tensor tymapni do?

Answer 4

It tightens the tympanic membrane to dampen large sounds

Question 5

Embryological precursors of the external ear?

Answer 5

1st pharyngeal cleft and 1st and 2nd pharyngeal arches

Question 6

Embryological precursors of the middle ear?

Answer 6

1st pharyngeal pouch

Ossciles from 1st and 2nd pharyngeal arches

Question 7

Embryological precursors of the inner ear?

Answer 7

Otic vesicle

Question 8

What does the otic vesicle start as during development?

Answer 8

Hindbrain induces a set of otic placodes

The placodes invaginate to form otic pits and then otic vesicles

Question 9

Otic vesicles differentiate into dorsal and ventral parts. What do these two regions become?

Answer 9

Dorsal part becomes - semicirculars ducts, utricle, and enodlympahtic duct

Vental part becoems saccule, cochlea, etc

Question 10

What splits to form the spiral and vestibular ganglia?

Answer 10

Statoacoustic ganglion

Question 11

What goes on to form the tympanic cavity and eustachian tube?

Answer 11

The first pharyngeal puch

Question 12

AGAIN

Stepedius and tensor tympani muscles are formed by what embryological derivatives?

Answer 12

Tensor tympani - 1st pharyngeal arch

Stapedius - 2nd pharyngeal arch