Palate Flashcards
When does the formation of the palate take place?
What is the primary palate?
Role of the secondary palate?
- weeks 6-12
- initially common oro-nasal cavity
Primary palate: demarcates oral vs nasal components
- derived from fused medial nasal priminences and intermaxillary segment
Secondary palate:
- separates the nasal airway and oral cavity
- important for: mastication - bolus formation
- sensation - taste and texture
- speech
What happens at week 6 of palate development?
Week 7?
Beginning of week 8?
Week 6: ectomesenchyme proliferates to form nasal septum, and palatal shelves, at the same time as the tongue growing upwards
Week 7: lateral palatal shelves are vertically orientated as insifficient space due to large tongue, fill space but do not attach to tongue
Beginning of week 8: (sometimes 7 for males) - palatal shelves flip into horizontal orientation, tongue withdraws downwards
What are the two theories for palatal shelf elevation?
Forces extrinsic to the palate:
- head lifting fro cardiac plate
- meckels cartilage growth
Intrinsic forces generated within the palate:
- hydration of ECM: hyaluronan (GAG): binds 10x its own weight in water –> turgidity, making palatal shelves very turgid allowing them to flip quickly
- mesenchymal cells appear to shorten - contractile microfilaments which produces a force
- forces directed via collagen fibres
- altered blood flow allowing shelves to elevate
What happens from week 9-12?
Week 9-12: palatal shelves begin to fuse from the front to back, primary palate, down secondary shelves to back of mouth via true fusion
What are some fusion problems?
- failure to fuse: completely or incompletely - cleft palate
- epithelial remnants: cell rests, cystic potential causing pain within the roof of the mouth
Risk factors for cleft palates: smoking, alcohol abuse, drugs (medicinal and recreational), viruses, rubella, too much vitamin A (or other retinoids) and deficiencies in folic acid
