embryo

Question 1

5 ____ develop as bulging prominences around the ____ during week 4

Answer 1

facial primordia; stomodeum

Question 2

5 different primordia include:

Answer 2

frontonasal prominence (rostral to stomodeum)
maxillary prominences (lateral to stomodeum)
mandibular prominences (caudal to stomodeum)

Question 3

____ separates the primitive oral cavity from the developing GI tract and disintegrates during the early 5th week

Answer 3

buccopharyngeal membrane

Question 4

most facial structures develop during weeks ____ which is during the _____

Answer 4

4-8 (2nd month); embryonic period

Question 5

during fetal period, ___ expands to accompany the growing brain, which causes the eyes to shift ____

Answer 5

cranium; anteriorly and medially

Question 6

during the fetal period, the ____ move superiorly and the ___ becomes more prominent

Answer 6

ears; nose

Question 7

proportions of the facial skeleton become more normal once the _____ grow and once fetus acquires ____

Answer 7

maxilla and mandible grow (to allow space for teeth)

paranasal sinuses

Question 8

at the end of the 4th week, 2 ____ thickenings develop within the frontonasal prominence, called the _____

Answer 8

ectodermal; nasal placodes

Question 9

____ surrounding the placodes proliferates, forming elevations called:

Answer 9

mesenchyme

medial and lateral nasal prominences (2 of each)

Question 10

during the 5th week, epithelium of nasal placodes sinks down into underlying mesenchyme to form depressions called ____, which will become the future ____

Answer 10

nasal pits; nostrils (nares)

Question 11

the nasal pits will deepen and expand dorsally to form ____, which will form the ____

Answer 11

nasal sacs; right and left nasal cavities

Question 12

____ separates nasal cavities from oral cavity; ruptures at the end of week 6

Answer 12

oronasal membrane

Question 13

after rupture of oronasal membrane, nasal and oral cavities are now in communication through ____

Answer 13

primordial choanae

Question 14

development of the ____ establishes the definitive choanae, separating the ____

Answer 14

secondary palate ; nasal cavity from nasopharynx

Question 15

____ gives rise to olfactory epithelium

Answer 15

neuroectoderm

Question 16

____ develop from lateral walls of the nasal cavity

Answer 16

nasal conchae

Question 17

____ prominences fuse at the midline first to create a smooth jawline

Answer 17

mandibular

Question 18

maxillary prominences grow in size and move medially, compressing the ____ in the midline, causing them to fuse

Answer 18

medial nasal prominences

Question 19

cleft between lateral nasal prominences and maxillary prominences is the _____; it is lost once the prominences fuse

Answer 19

nasolacrimal groove

Question 20

____ proliferates into underlying ____ and forms a solid rod that separates from the surface and canalizes to become the ____

Answer 20

ectoderm; mesenchyme; nasolacrimal duct

Question 21

superior end of nasolacrimal duct dilates to form ____ and inferior end opens up into _____

Answer 21

nasolacrimal sac; inferior meatus of the nasal cavity

Question 22

medial nasal prominences fuse to form the ____

Answer 22

intermaxillary segment

Question 23

intermaxillary segment consists of:

Answer 23

• philtrum of upper lip (labial component)
• premaxillary part of maxilla (upper jaw comp); 4 incisors and assoc gingiva
• primary palate (palatal comp; the primary hard palate is only the most anterior portion of the hard palate)

Question 24

secondary palate is composed of:

Answer 24

remainder of hard palate + soft palate + uvula

Question 25

during week 6, two plates of mesenchyme, _____, extend medially from the maxillary prominences

Answer 25

lateral palatine processes

Question 26

palatine processes project ____, then swing upwards to assume ____ position, and fuse with ____, ____, and ____

Answer 26

inferomedially ; horizontal; each other, primary palate, and nasal septum

Question 27

____ marks where secondary palate fuses with primary palate and is used to indicate ant and post palatal defects

Answer 27

incisive foramen

Question 28

____ marks where lateral palatine processes fused together

Answer 28

median palatine raphe

Question 29

____ and ____ will ossify forming the bony hard palate

Answer 29

primary palate; anterior portion of secondary palate

Question 30

cleft lip (with or without cleft palate) is an ____ palatal defect caused by failure of :

Answer 30

anterior; medial nasal prominences to fuse with maxillary prominences on one or both sides

Question 31

during week 4, the inner ear is the first to develop as a bilateral thickening in ____ at the level of the ____; these bilateral thickenings are called ____

Answer 31

surface ectoderm; caudal hindbrain; otic placodes (2)

Question 32

ectoderm invaginates in each placode, forming an ____, the edges of which pinch off to form an ____ that separates from surface ectoderm and will become the ____ for each ear

Answer 32

otic pit; otic vesicle; membranous labyrinth

Question 33

____ extends from otic vesicle to form the _____

Answer 33

diverticulum; endolymphatic duct and sac

Question 34

2 regions of the otic vesicle

Answer 34

``` utricular region (dorsal): utricle and semicircular ducts saccular region (ventral): saccule and cochlear ducts ```

Question 35

the ____ grows out as an extension from the saccular region and coils to form the _____

Answer 35

cochlear duct; membranous cochlea

Question 36

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

Answer 36

perilymphatic space

Question 37

2 divisions of the perilymphatic space, both filled with perilymph

Answer 37

scala vestibuli and scala tympani

Question 38

cartilage surrounding the cochlear duct ____ to form the ____ encasing the inner ear structures

Answer 38

ossifies; bony labyrinth

Question 39

cells in walls of coiled duct form the _____

Answer 39

spiral organ of Corti

Question 40

cell bodies of ____ migrate along coils of cochlear duct and form the ____

Answer 40

CN VIII; spiral ganglion

Question 41

middle ear cavity is also called ____

Answer 41

tympanic cavity

Question 42

malleus and incus are associated with pharyngeal arch ___

Answer 42

1

Question 43

stapes is associated with pharyngeal arch ___

Answer 43

2

Question 44

_____ is from the first pharyngeal groove or cleft and the ___ is from the first pouch

Answer 44

external acoustic meatus; middle ear

Question 45

tympanic membrane is made up of ____

Answer 45

ectoderm and endoderm

Question 46

the auricle or pinna of the external ear develops from ______ : mesenchymal proliferations surrounding the _____ (mesenchyme from 1st and 2nd pharyngeal arches)

Answer 46

6 auricular hillocks; 1st pharyngeal groove

Question 47

auricles develop at level of ____ but will shift to final position which is at ___ level

Answer 47

1st pharyngeal groove; eye

Question 48

the lens is derived from the invagination of ____

Answer 48

surface ectoderm

Question 49

the outer layer of the optic cup becomes the ____ and the inner layer of the optic cup becomes the ____

Answer 49

retinal pigmented epithelium; neural retina

Question 50

rod and cone photoreceptors are adjacent to the ____, in the outermost layer of the retina

Answer 50

pigmented epithelium

Question 51

remnant of the ____ in the vitreous body remains in the adult

Answer 51

hyaloid artery (called the hyaloid canal)

Question 52

the ____ is incorporated into the ____ in the adult

Answer 52

central retinal a. ; optic n.

Question 53

"key hole" appearance of the iris due to failure of the retinal fissure to close during the 7th week

Answer 53

coloboma

Question 54

outer layer of the cornea is continuous with _____

Answer 54

surface ectoderm

Question 55

the middle layer of the cornea is derived from ____

Answer 55

mesoderm

Question 56

migrating mesenchyme from neural crest cells contribute to the ____ and ____

Answer 56

iris; cornea

Question 57

the iris forms from ____ which is from _____

Answer 57

mesenchyme; migrated neural crest cells

Question 58

the cornea is induced by the ____

Answer 58

lens

Question 59

cornea layers

Answer 59

outer: ectoderm | middle and inner: mesenchyme (migrated neural crest)