Week 3.0 - Development of the nose and face Flashcards
(32 cards)
What are neural crest cells?
-Specialised population of cells, present throughout the body, that arise within the lateral neuroectoderm
What happens to neural crest cells upon fusion of the neural tube?
-Displaced into mesoderm
What is the palpebral fissure?
-Spece between eyelids
What is the philtrum?
-Groove in upper lip
From where is the facial skeleton derived?
-Neural crest of first pharyngeal arch
Where do MoM arise from?
-Mesoderm of 1st Ph Arch
Where do muscles of facial expression arise from?
-Mesoderm of 2nd Ph Arch
What contributes to the facial primordia?
- 1st pharyngeal arch
- Frontonasal Prominence
From where does the primordia of the eyes originate
-Frontonasal prominence
What is stomatoduem?
-Buccopharyngeal membrane -> primordia of the mouth
State the external features which arise from the frontonasal prominence
- Forehead
- Bridge of nose
- Nose
- Philtrum
- Primary palate
State the external features which arise from the maxillary prominence of the 1st pharyngeal arch
- Cheeks
- Lateral upper lip
- Lateral upper jaw
- Secondary palate
State the external features which arise from the mandubular prominence of the 1st pharyngeal arch
-Lowet lip and jaw
Where do the nasal placodes first appear? How?
- Frontonasal prominence
- Thickening of the ectoderm
Describe the formation of the nose
- Nasal placodes appear on FNP
- Cells begin to differentiate and the placodes sink to form nasal pits
- Medial growth of maxillary prominence pushes nasal prominence close together in midline
- Maxillary prominences fuse with nasal prominences
- Further maxillary prominence growth pushes medial nasal prominences together which then fuse
What is the intermaxillary segment during facial development?
- Formed by fusion of medial nasal prominences
- > philtrum, upper jaw and primary palate
What is the main section of the definitive palate?
-Secondary palate during development
How is the nasal cavity initially separated from the oral cavity in facial development?
-Oronasal membrane
From where does the primary palate arise?
-Intermaxillary segment
From where does the secondary palate arise?
-From the palatal shelves from the maxillary prominence
Describe the development of the secondary palate
- Palatal shelves grow downwards into the oral cavity on each side of the developing tongue
- Mandible grows large enough to allow tongue to drop downwards
- Palatal shelves grow towards each other and fuse in the midline as the maxillary prominence develop
Describe formation of nasal septum
-Grows down the midline and fuses with palatal shelves
Why are the lip and palate described as being of dual origin?
- Primary palate and philtrum from intermaxillary segment from medial nasal prominences (FNP)
- lip and Secondary palate from maxillary prominence
What is a lateral cleft lip?
-Failure of fusion of the medial nasal prominence and the maxillary prominence
