Development of Orofacial Structures

Question 1

Neurocranium derived from, gives rise to

Answer 1

Derived from mesenchyme

Gives rise to bones that enclose the brain

Question 2

Viscerocranium derived from, gives rise to

Answer 2

Derived from mesenchyme

Gives rise to bones that comprise the facial skeleton

Question 3

Intramembranous ossification

Answer 3

Mesenchymal origin w/o cartilage formation

Osteoblasts deposit osteoid

Question 4

Endochondral ossification

Answer 4

Pre-existing cartilaginous model

Primary ossification center, chondrocyte hypertrophy

Question 5

Craniosynostosis

Answer 5

Premature fusion of cranial sutures

Question 6

Scaphocephaly

Answer 6

Sagittal suture

Long, narrow, wedge shaped cranium- most common

Question 7

Brachycephaly

Answer 7

Entire coronal suture

High, tower-like cranium

Question 8

Plagiocephaly

Answer 8

One side of coronal suture

Twisted and asymmetric

Question 9

Trigonocephaly

Answer 9

Frontal/metopic suture

Question 10

Derivatives of frontal and lateral nasal prominences

Answer 10

Frontal- forehead, dorsum/apex of nose

Lateral- alae of nose

Question 11

Derivatives of medial nasal prominence

Answer 11

Nasal septum
Ethmoid bone
Cribriform plate

Question 12

Derivatives of maxillary/mandibular prominences

Answer 12

Maxillary- upper cheek, upper lip

Mandibular- chin, lower lip, cheek

Question 13

Formation of lower jaw and lip

Answer 13

First parts of face to form
Oropharyngeal membrane disintegrates, merging of medial ends of mandibular prominences
Incomplete fusion results in chin dimple

Question 14

Maxillary prominence forming into lip, maxilla, secondary palate

Answer 14

Maxillary prominences grow medially, merge laterally with mandibular prominences

Question 15

Nasal placodes

Answer 15

Bilateral oval thickenings of surface ectoderm on inferolateral portion of frontonasal prominence
Proliferation causes horse-shoe shaped elevations
These result in primordial nares and nasal prominences

Question 16

Auricular primordia

Answer 16

Six auricular hillocks form around first pharyngeal groove

Development of mandible pushes ears from neck to side of head

Question 17

Which signaling molecule is responsible for development of mandibular processes and removing webbing from the hands/feet

Answer 17

BMP

Question 18

Primordial chonae

Answer 18

Connection between nasopharynx and nasal cavity

Question 19

Formation of primary palate

Answer 19

Fusion of medial nasal prominences forms median palatine process
Located b/w maxillary prominences
Forms premaxillary part of maxilla

Question 20

Secondary palate formation

Answer 20

Develops from lateral palatine processes

Mesenchymal projections extending from internal aspects of maxillary prominences

Question 21

Nasal septum

Answer 21

Downward growth of internal parts of merged medial nasal prominences
Fuses with lateral palatine processes from anterior to posterior

Question 22

Choanal atresia

Answer 22

Associated with bony abnormalities of the pterygoid plates and midfacial growth abnormalities
Presents as upper airway obstruction, noisy breathing, or cyanosis that worsens during feeding and improves with crying
Can be part of Treacher-Collins, CHARGE, Kallman, or VACTERL syndromes

Question 23

Anterior 2/3rds tongue growth is induced by

Answer 23

Mesenchyme from pharyngeal arch 1

Question 24

What induces the pharyngeal parts of the tongue- the copula and hypopharyngeal eminence

Answer 24

Copula- PA2
Hypopharyngeal eminence- PA3/4
Hypopharyngeal eminence overgrows copula, terminal sulcus is where fusion of oral and pharyngeal parts occurs

Question 25

Tongue musculature is derived from

Answer 25

Myoblasts of occipital myotomes

Question 26

Taste buds are innervated by

Answer 26

Glossopharyngeal nerve

Question 27

Glossoschissis

Answer 27

Bifid tongue

Question 28

Macroglossia

Answer 28

Associated with Beckwith-Wiedmann and Down Syndromes mucopolysaccharidoses

Question 29

Odontogenesis is induced by

Answer 29

Communication between neural crest cells and oral epithelium

Question 30

Dental papilla formed by, made up of

Answer 30

Formed by odontoblasts

Made up of dentin and pulp-comprises inner part of tooth

Question 31

Which teeth erupt first

Answer 31

Mandibular

Question 32

Ameloblasts

Answer 32

Inner enamel epithelium differentiates in response to dentin production
Ameloblasts form enamel

Question 33

Dental follicle/sac

Answer 33

Mesenchyme surrounding dental papilla and enamel organ

Cementum

Question 34

Enamel formed by what tissue

Answer 34

Ectoderm