Ear and Eye Embryology

Question 1

What embryological fissure is responsible for the formation of the eye?

Answer 1

optic groove

Question 2

Hyaloid arteries supply what?

Answer 2

lens, gone before birth

Question 3

Congenital coloboma

Answer 3

defective closure of the optic fissure/optic fissure

Question 4

Optic nerve is extension of what structure?

Answer 4

diencephalon

Question 5

Optic vesicles evaginate from the

Answer 5

diencephalon

Question 6

This surrounds the hyaloid blood vessels

Answer 6

optic stalk

Question 7

The retina develops from the

Answer 7

optic cup

Question 8

The two layers of the retina are:

Answer 8

RPE (retinoid pigmented epithelium)

photoreceptors

Question 9

Ora serrata

Answer 9

boundary of photosensitive and non-photosensitive areas of the retina

Question 10

The iris develops from…

Answer 10

RIM of the optic cup

Question 11

These two muscles are developed from neuroectoderm cells

Answer 11

sphincter and dilator palpillae

Question 12

The lens develops from

Answer 12

surface ectoderm (lens placode)

Question 13

Lens placode forms the

Answer 13

lens pit

Question 14

Lens bit forms

Answer 14

lens vesicles

Question 15

This artery supplies the developing lens

Answer 15

hyaloid artery

Question 16

Does a persistant hyaloid artery cause vision defects?

Answer 16

yes

Question 17

What is the embryological origin of the vitreous humor?

Answer 17

mesenchyme

Question 18

What is the origin of the aqueous humor?

Answer 18

ciliary processes

Question 19

Choroid in sclera are formed from ______ induced by ______

Answer 19

mesenchyme, RPE

Question 20

Cornea is derived from _____ induced by _____

Answer 20

surface ectoderm, lens vesicle

Question 21

Conjunctiva is derived from

Answer 21

surface ectoderm

Question 22

Coloboma

Answer 22

failure of optic fissure to close

• anterior defect asymptomatic
• posterior defect may cause visual field problems

Question 23

Mesenchyme forms which layer of the inner ear?

Answer 23

bony labyrinth

Question 24

Notochord and paraxial mesoderm signal thickens of surface ectoderm called

Answer 24

otic placodes

Question 25

When are the otic placodes formed?

Answer 25

about 22 days

Question 26

otic placodes => otic pits => otic vesicles => ??

Answer 26

membranous labyrinth

Question 27

Dorsal otic vesicle gives rise to what?

Answer 27

semicircular canals
utricle
endolymphatic duct

Question 28

Ventral otic vesicle gives rise to what?

Answer 28

saccule
cochlear duct
ductus reuniens

Question 29

Where in the skull does the inner ear form?

Answer 29

petrous portion of temporal bone

Question 30

What type of ossification does the cartilangeous otic capsule undergo?

Answer 30

endochondral ossification

Question 31

Malleus and incus pharyngeal arch

Answer 31

1

Question 32

Stapes pharyngeal arch

Answer 32

2

Question 33

Tensor tympani innervation

Answer 33

V3

Question 34

Stapedius innervation

Answer 34

VII

Question 35

External ear pharyngeal arch derivative

Answer 35

1

Question 36

Meatal plug

Answer 36

present from 3-7 mo.

upon degeneration helps form tympanic membrane

Question 37

Sensation to tympanic membrane

Answer 37

V
VII
IX
X

Question 38

External ear malformation

Answer 38

many causes

Question 39

Neurosensory deafness

Answer 39

abnormal cochlea, VIII, or brainstem

Question 40

Infectious cause of congenital neursensory deafness

Answer 40

rubella

Question 41

Conduction deafness: congenital cause

Answer 41

persistence of meatal plug