CFD6- Development of the face and maxilla

Question 1

what is the front-nasal process?

Answer 1

Prominence in the upper facial area at the most cephalic end of the embryo

Question 2

what is the cephalic end?

Answer 2

Head end of a structure such as the trilaminar embryonic disc

Question 3

what are the mandibular processes?

Answer 3

Processes of first branchial arch that fuse at the midline to form mandibular arch

Question 4

what is the mandibular arch?

Answer 4

Lower dental arch with mandibular teeth or the 1st Branchial/Pharyngeal arch inferior to the stomodeum in the embryo

Question 5

what are the maxillary processes?

Answer 5

Prominence from mandibular arch that grows superiorly and anteriorly on each side of the stomodeum of the embryo

Question 6

what is the maxillary arch?

Answer 6

Upper dental arch in which the maxillary teeth form

Question 7

what is the nasal placode?

Answer 7

Placodes that develop into olfactory organ for the sensation of smell located in the mature nose

Question 8

what is the placode?

Answer 8

Area of ectoderm found at the location of the developing special sense organs on the embryo

Question 9

when does development of the face start?

Answer 9

4 weeks

Question 10

where does the face begin to develop?

Answer 10

squeezed between the brain and developing heart

Question 11

what layers are involved in facial development?

Answer 11

all 3 embryonic layers

Question 12

what are the five facial processes?

Answer 12

• Frontonasal prominence
• 2 paired maxillary
• 2 paired mandibular

Question 13

what is “fusion”?

Answer 13

• “fusion” of prominences by elimination of furrow

- between medial nasal prominences

Question 14

what is true fusion?

Answer 14

True fusion of separate processes between medial nasal prominence and maxillary process

Question 15

what is a result if true fusion does not occur?

Answer 15

cleft palate

Question 16

what membrane disintegrates in the stomodeum?

Answer 16

temporary membrane

Question 17

what chamber is formed?

Answer 17

oro-nasopharyngeal chamber

Question 18

what is the primary palate?

Answer 18

– from the fused medial nasal prominence (intermaxillary segment)
– does not separate oral and nasal cavities - demarcates

Question 19

where are placodes located?

Answer 19

all on the same level

Question 20

How do the eyes move during development of the face?

Answer 20

move from the side of the face inwards

Question 21

How does the maxillary process develop?

Answer 21

develop across and fill the gap

Question 22

at 7 weeks , what stage is development at?

Answer 22

true fusion has occurred and this is the flat face

Question 23

what happens at 10 weeks?

Answer 23

all structures are fully formed and now cartilage and bone will be laid

Question 24

what has formed at the 4th week?

Answer 24

– primitive stomodeum bounded by
– FNP, max. and mand. process
– nasal placodes, develop into nasal pits

Question 25

what has formed at the 5th week?

Answer 25

– nasal pit surrounded by lateral + medial nasal | prominence

Question 26

what has formed at the 6th and 7th week?

Answer 26

Medial nasal prominences fuse together and fuse with maxillary processes

Question 27

what is the frontonasal contributions to the face?

Answer 27

forehead, bridge of nose

Question 28

what is the medial nasal contributions to the face?

Answer 28

philtrum of the lip, crest and tip of nose

Question 29

what is the lateral nasal contributions to the face?

Answer 29

alae of nose

Question 30

what is the maxillary contributions to the face?

Answer 30

cheeks, lateral upper lip

Question 31

what is the mandibular contributions to the face?

Answer 31

lower lip

Question 32

what actions does the mesenchyme have?

Answer 32

- streams of mesenchyme migrate and proliferate to lay matrix - ectodermal will stop and differentiate into cartilage - mesodermal produce a lot of matrix and grow down and bind to the tongue

Question 33

what is the first sign of the tooth development?

Answer 33

6 weeks - primary epithelial band

Question 34

when does the nasal septum form ?

Answer 34

week 7

Question 35

what produces cartilage of the nose?

Answer 35

chondroblasts

Question 36

Describe the nasal cartilage.

Answer 36

- Mesenchymal condensation -  Primary support for developing maxilla -  continuous with the cartilages of the cranial base

Question 37

what is the area between the maxilla?

Answer 37

intermaxillary segment

Question 38

Describe the ossification -bone formation.

Answer 38

- 6-7th week - mandible - 8th week - maxilla - 8th week - palate and nasal capsule

Question 39

what are the 2 methods of osteogenesis?

Answer 39

- intramembranous | - endochondral

Question 40

what ossification produces most of the bones of the face?

Answer 40

intramembranous

Question 41

Describe the intramembranous ossification.

Answer 41

-  Mesenchymal cells → osteoblasts  - Osteoblasts deposit osteoid.... -  Mineral deposited -  Osteoblasts trapped → osteocytes

Question 42

where is the primary centre of ossification in the maxilla?

Answer 42

– maxillary process – near nasal capsule – between the infraorbital nerve and its ant. sup. alv. branch

Question 43

what is the 4 types of maxilla?

Answer 43

- frontal process - palate - zygomatic - alveolus

Question 44

describe the pre maxilla in animals.

Answer 44

– separate premaxilla | – separate intermaxillary ossification centres

Question 45

is there pre maxilla in humans?

Answer 45

no

Question 46

Describe formation of the vomer.

Answer 46

- week 8 - Develops in inferior aspect of the nasal septum - intramembranous

Question 47

Describe the control of pattern formation.

Answer 47

-Retinoic acids -Five growth factors families implicated in the facial development: BMP, FGF, Shh, Wnt and endothelins

Question 48

what do the growth factors control?

Answer 48

proliferation, survival and apoptosis

Question 49

Describe clinical aspect of facial development.

Answer 49

- Cleft lip around 1:1000 births. Can be unilateral of bilateral. - Genes or environmental factors. - Genes include Dlx 1/2/5/6 affects FGF8, Sonic Hedgehog, EGF amd BMP4. - Failure of fusion of maxillary process with medial nasal process