Development of the Face, Palate and Nasal cavities Flashcards
What is the 1st pharyngeal arch the origin of?
Maxilla Mandible Zygomatic arrch Temporal (sqaumous) Muscles of masicaltion
What is the 2nd pharyngeal arch responsible for?
Muscles of facial expression
How many facial swellings are present from week 4?
5
What are the 5 facial swellings?
Frontonasal prominence (with nasal placodes) Maxillary prominence (x2) Mandibular prominence (x2)
What surrounds the primitive oral cavity?
Stomodeum
What forms the nasal placodes?
Ectodermal thickenings on the frontonasal prominence
When does facial development occur?
weeks 4-10
When do the additional nasal swellings begin to develop?
week 5
What are the 4 additional nasal swellings?
Medial nasal swellings (x2)
Lateral nasal swellings (x2)
Where does ear development begin?
Lower cervical region
Week 7
Frontonasal prominece moves down
Nasal pit becomes deeper
Eyes begin to develop
Medial nasal prominences move medially towards each other
Where is the nasal lacrimal groove?
Between the maxillary prrominence and the lateral nasal prominence
How does the nasolacrimal groove become the nasolacrimal duct?
Solid epithelial cord in the floor of groove
Cord detaches from the ectoderm
Canalization forms the nasolacrimal duct
What is the intermaxillary segment?
Medial nasal prominences coming together
What makes the upper lip?
2 medial nasal prominences
2 maxillary prominences
What makes the lower lip?
Mandibular prominences
What makes the bridge and nasal septum?
Frontonasal prominences
What makes the crest and tip of the nose?
Medial nasal prominences
What makes the alae of the nose?
Lateral nasal prominences
When does the palate begin to develop?
Week 7
What gives rise to the primary palate?
Fusion of medial nasal prominences give: intermaxillary segment
What does the labial portion of the intermaxillary form?
Philtrum of upper lip
What does the upper jaw component of the IM segment form?
Carries 4 inscisors
What does the palatal components form?
Primary palate
What has been formed at week 10?
??
What happens to the nose between late 5th week and late 6th week?
Nasal pits deepen and penetrate into the underlying mesenchyme with forward growth of frontonasal prominence
Intermaxillary segment is connected by a nasal fin
Nasal fin vacuolizes and thins, this opens the developing nasal sac
What happens during the 7th week of development?
Nasal cavities communicate with oral cavity via primitive choanae behind primary palate
Definite choeanae open at juntion of nasal cavity with pharynx due to formation of secondary palate
Where do the palatal shelves develop?
Parallel to the tongue
Where do the palatal shelves fuse?
In the central region then expand anteriorly and posteriorly
What facilitates clearance of the tongue?
Mandibular development
Why is cleft palate more common in females?
Palatal development is delayed by a week in females
longer time for something to go wrong
Which side is cleft lip more common?
Left
Which gender is cleft lip more common in?
Males
