E1 Dev Of Face, Nose, Ears, Eyes

Question 1

5 Facial primordia develop as bulging prominences around stomodeum:

Answer 1

• Frontonasal Prominence (1)
• Maxillary Prominences (2)
• Mandibular Prominences (2)

Question 2

End of 4th week: 2 ectodermal thickenings develop within frontonasal prominence:

Answer 2

Nasal Placodes

Question 3

Mesenchyme surrounding the nasal placodes proliferates forming elevations:

Answer 3

Medial Nasal Prominences (2)

Lateral Nasal Prominences (2)

Question 4

Epithelium of nasal placodes sinks down into underlying mesenchyme to form depressions:

Answer 4

Nasal pits (future nostrils)

Question 5

Both nasal sacs will form the _____

Answer 5

Right and left nasal cavities

Question 6

The _____ separates nasal cavities form oral cavity; it ruptures at end of week 6 to form communication between cavities through _____

Answer 6

Oronasal Membrane

Primordial Choanae

Question 7

Development of secondary palate establishes the definitive ____ separating nasal cavities from nasopharynx.

Answer 7

Choanae

Question 8

_____ gives rise to Olfactory epithelium

Answer 8

Neuroectoderm

Question 9

Cleft between lateral nasal prominences and maxillary prominences. Lost when lateral nasal prominences fuse with maxillary prominences.

Answer 9

Nasolacrimal Groove

Question 10

Ectoderm proliferates into underlying mesenchyme and forms a solid rod that separates from surface and canalizes to become ____. Superior end forms a sac, inferior end opens up into inferior meatus of nasal cavity.

Answer 10

Nasolacrimal Duct

Question 11

Medial nasal prominences fuse -> Intermaxillary Segment:

Answer 11

• Philtrum of upper lip
• Premaxillary part of maxilla
• 4 incisors/gingiva
• Primary Palate (most anterior part of hard palate)

Question 12

Remainder of hard palate and soft palate and uvula

Answer 12

Secondary Palate

Question 13

Marks where secondary palate fuses with primary palate; used to indicate anterior and posterior palatial defects

Answer 13

Incisive Foramen

Question 14

Marks where lateral palatine processes fused together

Answer 14

Median Palatine Raphe

Question 15

Anterior palatal defect caused by failure of medial nasal prominences to fuse with maxillary prominences on one or both sides.

Answer 15

Cleft Lip (w or w/o Cleft Palate)

Question 16

When tongue doesn’t drop and blocks fusion of lateral palatine processes, a _____ will result.

Answer 16

Cleft Palate

Question 17

Inner ear develops as a bilateral thickening in surface ectoderm at level of caudal hindbrain:

Answer 17

Otic Placodes (2)

Question 18

Ectoderm invaginates in each Otic Placode, forming an ____, the edges of which pinch off to form an ____ that separates from surface ectoderm to eventually become ____.

Answer 18

Otic Pit

Otic Vesicle

Membranous Labyrinth

Question 19

Diverticulum extends from otic vesicle to form the _____

Answer 19

Endolymphatic Duct and Sac

Question 20

Utricle + Semicircular Ducts =

Answer 20

Utricular Region

Question 21

Saccule + Cochlear Ducts

Answer 21

Saccular Region

Question 22

Grows out as extension from saccular region and coils to form the membranous cochlea

Answer 22

Cochlear Duct

Question 23

Vacuoles develop in cartilage surrounding cochlear duct and unite to form the ____.

Answer 23

Perilymphatic Space (Scala Vestibuli and Scala Tympani, both filled with perilymph)

Question 24

The cochlear duct grows out as extension from saccular region and coils to form the membranous cochlea. Cells in walls of coiled duct form the ____

Answer 24

Spiral Organ of Corti

Question 25

Cell bodies of CN VIII migrate along coils of cochlear duct and form ____

Answer 25

Spiral Ganglion

Question 26

External ear (auricle/pinna) develops from _____ (mesenchymal proliferations surrounding 1st pharyngeal groove)

Answer 26

Auricular Hillocks

Question 27

Key hole appearance of iris due to failure of retinal fissure to close in 7th week

Answer 27

Coloboma

Question 28

Eyelids develop from ______. They are fused until they open in week 28.

Answer 28

Mesenchyme (migrated neural crest)