Orofacial Development: Palate and Jaw

Question 1

three stages of primary palate formation and upper lip

Answer 1

1. formation of inter-maxillary segment
2. nasal septum of developing ethmoid
3. differentiation of intermaxillary segment

Question 2

during stage 1, intermaxillary segment develops due to what

Answer 2

fusion of medial nasal process of frontonasal region

Question 3

during stage 2, how does nasal septum of ethmoid grow

Answer 3

inferiorly from roof of nasal cavity toward oral cavity

Question 4

what are the 2 components of intermaxillary segment

Answer 4

1. labial (philtrum of upper lip)
2. palatal (primary palate containing max incisors will ossify by intramembranous)

Question 5

formation of upper lip involves fusion of what regions of soft tissue

Answer 5

1. labial component of max process
2. labial part of intermaxillary segment (philtrum) (outer red)

Question 6

what stage:

proliferation of neural crest derived mesenchyme (ectomesenchyme) in lateral palatal shelves of maxillary process

Answer 6

stage 1 prior to palatal elevation

Question 7

what stage:

palatal shelves lie in vertical orientation located on either side of tongue

Answer 7

stage 1 prior to palatal elevation

Question 8

what must happen before palatal shelves can elevate to a horizontal position

Answer 8

lower jaw needs to grow forward, pulling tongue downward into floor

Question 9

what stage:

lower jaw grows forward, and tongue drops from nasal cavity into floor of mouth, creating room in oral cavity for shelf elevation

Answer 9

stage 2 - palatal shelf elevation

Question 10

palatal shelf elevation depends on what

Answer 10

proliferation of neuralcrest derived mesenchyme (ectomesenchyme) and increased synthesis of ECM proteins

Question 11

during stage 2, do palatal shelves move to a vertical or horizontal position

Answer 11

HORIZONTAL

Question 12

does the nasal septum continue its downward growth to separate nasal cavity into 2 chambers and fuse w/ secondary palate during stage 2

Answer 12

YES

Question 13

what stage:

bilateral fusion of palatal shelves anteriorly with primary palate (future premaxilla)

Answer 13

stage 3 - fusion and completion of palatogenesis

Question 14

what stage:

miidline fusion of lateral palatal shelves with each other = secondary palate

Answer 14

stage 3 - fusion and completion of palatogenesis

Question 15

fused palatal shelves fuse superiorly with ___

Answer 15

inferior edge of descending nasal septum

Question 16

the primary and secondary palates together form what?

Answer 16

definitive/complete adult palate

Question 17

signaling between ectoderm and ectomesenchyme is what kind of factor controlling palatal fusioin

Answer 17

intrinsic

Question 18

what are the intrinsic factors of palatal fusion

Answer 18

1. survival of ectomesenchyme and adequate proliferation allowing shelves to elevate and touth
2. apoptosiis of ectoderm - at medial epithelial seam
3. fusion/confluence of ectomesenchyme throughout completed palate
4. differentiation of remaining epithelium on palatal and nasal ssurface and differentiation of bone. muscle migrates into region

Question 19

growth of head and skull is what kind of factor controlling palatal fusion

Answer 19

extrinsic facttor

Question 20

what are the extrinsic factors of palatal fusion

Answer 20

1. downward and forward growth of mandible must occur to accomodate shelf elevation
2. growth of mandible lowers the tongue out of nasal cavity and into floor of oral cavity

Question 21

what is the location of a potential cleft to occur

Answer 21

site at which tissue merges or fuses together

Question 22

what is the boundary between primary and secondary palate

Answer 22

incisive foramen

Question 23

in order for fusion between palatal shelves to occur, what is required

Answer 23

breakdown/apoptosis of epithelium covering area between palatal shelves and at point of fusion with nasal septum

Question 24

what does breakdown of palatal shelf epithelium establish

Answer 24

confluence of neural crest derived mesenchyme (ectomesenchyme)

Question 25

when does ectomsenchyme begin to differentiate into bone and CT

Answer 25

following fusion of palatal shelves

Question 26

palatal skeletal muscles are derived from what

Answer 26

head mesoderm

Question 27

what stage: intramembranous ossification of anterior portion of palate occurs (forms definitive hard palate)

Answer 27

stage 4

Question 28

what are parts of hard palate

Answer 28

premacill, palatine process of maxiilla and palatiine bone

Question 29

where does skeletal muscle differentiate in palate

Answer 29

posterior portion of secondary palate - muscle of the soft palate

Question 30

muscles of soft palate originate from what? what is the exception?

Answer 30

paraxial/head mesoderm from region of 4th arch exception: tensor veli palatini is paraxial mesoderm of 1sts arch

Question 31

how many primary ossification sites are there? what are they?

Answer 31

1 - incisive foramen 4 - palatine foramen

Question 32

how does ossification around incisive foramen occur

Answer 32

spreads anterolateral

Question 33

how does ossification occur around palatine foramen occur

Answer 33

bilaterally spreads medial, anteriorly and posteriorly

Question 34

what type of growth occurs at secondary growth centers

Answer 34

appositional growth

Question 35

examples of secondary growth centers

Answer 35

1. sutural growth 2. secondary growth cartilages 3. displacement growth

Question 36

developmental structure and adult structred formed of: labial intermaxillary segment

Answer 36

DS: intermaxillary A: philtrum of lip - soft tissue/mucosa

Question 37

developmental structure and adult structure formed of: palatal intermaxillary segment

Answer 37

DS: primary palate A: premaxilla bone (derivative of intermaxillary process)

Question 38

developmental structure and adult structure formed of: labial maxillary processes 1st PA

Answer 38

DS: maxillary process A: upper lip - soft tissue/mucosa

Question 39

developmental structure and adult structure formed of: palatal component of maxillary processes 1st PA

Answer 39

DS: latteral palatal shelves A: secondary palate (palatine process of maxilla, palatine bone, and soft mucosa/soft CT)

Question 40

developmental structure and adult structure formed of: upper jaw component of maxillary processes 1st PA

Answer 40

DS: facial skeleton/membranous viscerocranium A: maxilla and alveolar process

Question 41

The _____ will contribute to the external and internal adult structures of the mid-face and upper jaw

Answer 41

1st PA maxillary process

Question 42

maxillary facial swelling/process is comprised of ___ covered externally with ___

Answer 42

ectomesenchyme; ectoderm

Question 43

what do swellings/processes differentiate into

Answer 43

soft CT/mucosa, cartilage, bone

Question 44

muscles from ___ PA contribute to lip and cheek

Answer 44

2nd

Question 45

the ___ contributes significantly to bones of facial skeleton which support midface

Answer 45

1st PA maxillary process

Question 46

developmental precursor, facial derivative, and adult structure of: external structures (soft tissue)

Answer 46

DP: 1st PA max process FD: 1st PA max processs AS: cheek and upper lip

Question 47

developmental precursor, facial derivative and adult structure of: internal structures (bony, soft, tissue/mucosa)

Answer 47

DP: 1st PA max process FD: lateral palatal shelves (form secondary) AND facial skeleton AS: maxilla, vomer, inferior concha, squamous part of temporal bone