development of the palate

Question 1

describe formation of the palate

Answer 1

• week 6-12
• Initially common oro-nasal cavity
• primary palate:
  
  • demarcates oral vs nasal components
  • derived from fused medial nasal prominences (part of FNP)
• inter-maxillary segment

Question 2

What is the role of the definitive (secondary palate)?

Answer 2

• separates the nasal airway + oral cavity
• important for:
  
  • mastication - bolus formation
• sensation - taste and texture
• speech

Question 3

describe palatal shelve elevation

Answer 3

Week 8
- Initially palatal shelves develop
- medially
- downwards

• Then palatal shelves:
• rapidly elevate
• grow towards each other

Question 4

palatal shelve elevation how?

Answer 4

• Forces extrinsic to the palate
  involving the tongue
• intrinsic forces generated within the palate

Question 5

palatal shelve elevation extrinsic factors

Answer 5

• tongue withdrawal due to:
  
  • head lifting from cardiac plate
  • meckel’s cartilage growth
  • increased height of nasal cavity
• True… but cause or facilitate elevation?
• Likely other factors involved…

Question 6

Palatal shelve elevation intrinsic factors

Answer 6

Intrinsic shelf force:
- hydration of extracellular matrix
- hyaluronan (GAG)
- bind 10x its weight in water - turgidity
- hyaluronan accumulates prior to elevation

Question 7

Palatal shelve elevation intrinsic factors (other theories)

Answer 7

• Mesenchymal cells:
  mesenchymal cells appear to shorten
  contractile microfilaments
• forces directed via collagen fibres??
• altered blood flow

Question 8

Answer 8