Face and Palate

Question 1

When does facial development begin?

Answer 1

During the 4th week (within the embryonic period but completes in the 12th week)

Question 2

What are the most common defects of the face?

Answer 2

Cleft Palate and Cleft Lip

Question 3

What are the 5 major facial prominences? (3 regions)

Answer 3

1-Frontonasal process
2-Maxillary processes (R and L)
3-Mandibular processes (R and L)
*each is an individual swelling

Question 4

What does the Frontal process become?

Answer 4

• intermediate structures:Medial and lateral nasal processes

- Adult structures: forehead, bridge of the nose, frontal and nasal bones

Question 5

What do the 2 mandibular processes become?

Answer 5

Adult structures: lower lip, lower face, lower cheek regions, chin, mandible, body of the tongue

Question 6

What do the two maxillary process become?

Answer 6

Adult structures: Midface, upper cheek regions, upper lip sides, secondary palate, maxilla, zygomatic bone, secondary palate

Question 7

What limits the depth of the stomodeum?

Answer 7

Oropharyngeal membrane

Question 8

What merge to form a single structure inferior to the enlarged stomodeum?

Answer 8

Mandibular processes

Question 9

How does merging or facial fusion take place?

Answer 9

tissue in the groove proliferates more rapidly than surrounding tissues to fill in

Question 10

What migrates into the furrow to help eliminate it?

Answer 10

Mesenchyme

Question 11

What does it mean to have a fusion of 2 processes?

Answer 11

There is a breakdown of surface epithelium where the junction takes place

Question 12

What are placodes?

Answer 12

specialized, thickened ectoderm found at the location of sense organs (i.e. 2 lens places on frontonasal process, 2 optic places posterolaterally)

Question 13

What type of epithelium develops from the nasal placodes after they submerge (also called nasal or olfactory pits)?

Answer 13

olfactory epithelium

Question 14

What temporary membrane separates the stomodeum from the nasal sac?

Answer 14

oronasal membrane

Question 15

What intermediate processes fuse together and form the middle of the nose, philtrum and tubercle of the upper lip?

Answer 15

medial nasal processes

Question 16

What does the intermaxillary segment develop from?

Answer 16

fused medial nasal processes

Question 17

what does the wedge shaped inter maxillary segment develop into?

Answer 17

Nasal septum, incisors and primary palate

Question 18

What do the lateral nasal processes fuse to form?

Answer 18

• alae

- they also fuse with the maxillary and medial nasal processes to form the nares

Question 19

What forms when the maxillary process fuses with each medial nasal process?

Answer 19

upper lip

Question 20

What does the nasal-optic groove become once eliminated by fusion?

Answer 20

nasolacrimal duct

Question 21

what does the bucconasal groove become once eliminated by fusion?

Answer 21

sides of the upper lip

Question 22

Two streams of ectomesenchyme of mandibular processes merge to form what?

Answer 22

Lower lip

Question 23

Cleft chin is a result of what?

Answer 23

failure of mandibular processes to fully fuse

Question 24

what main three ways can cleft lip form?

Answer 24

1-mesenchyme of inter maxillary segment fails to merge with maxillary prominence
2-failure of maxillary and medial nasal process fusion
3-failure of mesenchyme to grow beneath ectoderm to obliterate grooves

Question 25

What is characteristic of cleft lip? (how common etc.)

Answer 25

- more common and severe in males - 1:900 - more common unilaterally on left side

Question 26

When does palatal development begin?

Answer 26

5th week (within embryonic period)

Question 27

What are the two embryonic structures of the palate?

Answer 27

- primary: anterior 1/3 hard palate | - secondary: posterior 2-3 hard palate, uvula and soft palate

Question 28

during week 6-7 the maxillary processes gives rise to two what?

Answer 28

palatal shelves

Question 29

once the tongue begins to function, it contracts and moves out of the way of the what?

Answer 29

palatal shelves, which "flip up" because of BMP signaling

Question 30

what forms indicating fusion of the palatal shelves?

Answer 30

- under the mucosa: median palatine raphe | - in adult bone: median palatine suture

Question 31

In what direction does the palate fuse?

Answer 31

anterior to posterior

Question 32

What is characteristic of cleft palate? (how common etc.)

Answer 32

- 1:2500 - more common in girls - with or without cleft lip

Question 33

Where does the nasal septum develop?

Answer 33

grow inferiorly and deep to the medial nasal processes