Development Of Orofacial Structures Flashcards
What drives the shape and rate of growth of the head?
Brain development
What are the 5 facial primordia?
2 maxillary prominences
2 mandibular Prominences
1 frontonasal Prominences
When does the facial primordia develop?
Week 4
What does the facial primordia surround?
Stomodeum (primitive oral cavity)
How are the facial primordia separated from the primordial pharynx?
When did it rupture?
Oropharyngeal membrane
Ruptured day 26
What is the first part of the face to form and how?
Mandibular prominence (lower jaw and lip)
Oropharyngeal membrane will disintegrate
—> medial ends of mandibular prominence merge
What causes a chin dimple?
Incomplete fusion of the medial ends of the mandibular prominence
What signaling molecule is response for development of both mandibular processes?
BMP
What does the maxillary prominence make?
Upper lip, maxilla, secondary palate
How does the maxillary prominence grow?
Grows medial and merges laterallywith mandibular prominences
What are the primordial lips and cheeks invaded by?
What does this give rise to?
Invaded by Mesenchyme from PA 2
Gives rise to facial muscles
What are the derivatives of the frontal nasal prominence?
Forehead Rostral border of stomodeum and nose Dorsum/apex of nose Nasal placodes Medial and lateral nasal prominences
How are the nasal placodes formed?
What does proliferation of these lead to?
By bilateral oval thickening of surface ectoderm
Horse-shoe shaped elevations called medial and lateral nasal prominences (eventually form nasal pits)
What are the derivatives of the lateral nasal prominence?
Alae of nose
What are the derivatives of the medial nasal prominence?
Nasal septum
Ethmoid bone
Cribriform plate
What do the horse shoe shaped elevations from the proliferation of the nasal placodes form?
Nasal pits
What are nasal pits?
Primordial nares (nostrils)
How does the medial nasal prominence grow and what does it fuse with?
Shifted toward the midline bc of the medial growth of maxillary prominences
Regulated by PDGFRA
Fuses and forms intermaxillary segment (philtrum)
With what and when do the lateral nasal prominences fuse?
Merges with maxillary prominences by end of weak 6
Separated by these prominence by nasolacrimal ducts
When will the face have its characteristic form?
By 14 weeks (3 1/2 months)
What does the small appearance of the face prenatally result from?
Rudimentary upper and lower jaws
Unreported deciduous teeth
Small nasal cavities
Maxillary sinuses
What depresses and forms nasal pits?
Nasal placodes
What induces nasal pits to become deeper?
What does this form?
Mesenchyme from medial and lateral nasal prominences
Primordial nasal sacs
How do primordial nasal sacs grow?
Dorsal and ventrally to the forebrain