3.2 Development of the Nose and Face Flashcards
What is the neural crest?
Specialised population of cells that originates within the neuroectoderm
From where do the facial primordia originate?
1st pharyngeal arch and FNP
Where does the facial skeleton originate from?
Neural crest of 1st pharyngeal arch
Where do the muscles of mastication originate from?
Mesoderm of 1st pharyngeal arch
Where do the muscles of facial expression originate from?
Mesoderm of 2nd pharyngeal arch
What areas of the face is developed from the FNP?
Forehead, bridge of nose, nose, philtrum
What areas of the face is developed from the maxillary prominence of the 1st pharyngeal arch?
Cheeks, lateral upper lip, lateral upper law
What areas of the face is developed from the mandibular prominence of the 1st pharyngeal arch?
Lower lip and jaw
Describe how the nose develops
Endoderm thickens to produce nasal placodes on the FNP
Nasal placodes sink to form nasal pits
Medial and lateral nasal prominences (raised edges) form on either side of the pits
Maxillary prominences grow and push nasal prominences together in the midline
Two medial nasal prominences fuse in the midline
What forms due to the fusion of the nasal prominences?
Intermaxillary segment
What forms from the intermaxillary segment?
Philtrum, 4 incisors, Primary palate
How is the secondary palate formed?
Formed from palatal shelves derived from the maxillary prominences
How does a lateral cleft lip form?
Failure of fusion of medial nasal prominence and maxillary prominence
How does a cleft lip and a cleft palate form?
Failure of fusion of medial nasal prominence and maxillary prominence as well as failure of palatal shelves to meet in the midline
Describe how the eyes develop
Outpocketing of the forebrain
Overlying ectoderm differentiates to become optic placodes
The optic placode and underlying space (optic vesicle) invaginate and pinches off
As the facial prominences grow the eyes are pushed to the anterior of the face
