Development of palate Flashcards
What is the Role of the definitive (secondary) palate?
Role of the definitive (secondary) palate:
- separates the nasal airway + oral cavity
- Important for:
- Mastication – bolus formation
- sensation - taste and texture
- speech
When does the Palatal shelve elevation take place?
Week 8
- Initially palatal shelves develop
- medially
- downwards
- Then palatal shelves:
- rapidly elevate
- grow towards each other
How is the Palatal shelve elevation?
Forces extrinsic to the palate - Involving the tongue
Intrinsic forces generated within the palate
What are the Palatal shelve elevation Extrinsic factors?
- Tongue withdrawal due to:
- Head lifting from cardiac plate
- Meckel’s cartilage growth
- ↑ height of nasal cavity
What are the Palatal shelve elevation Intrinsic factors?
Intrinsic shelf force :
- Hydration of extracellular matrix
- Hyaluronan (GAG)
- bind 10x its weight in water – turgidity
- Hyaluronan accumulates prior to elevation
Another theory:
- Mesenchymal cells:*
- Mesenchymal cells appear to shorten*
- Contractile microfilaments*
What is Epithelial adhesion fusion?
- Sticky surface glycoprotein
- Specific - will not fuse with other epithelia e.g. tongue
What are the 3 theories about in fusion about how does mid-line disintegrate?
- Epithelial-Mesenchymal Transition
- Apoptosis of epithelial cells
- Migration to the nasal or oral edge
What are Fusion problems?
Failure to fuse - completely or incompletely - cleft palate
Epithelial remnants – Epithelial cell rests – Cystic potentia
What are the risk factors for palatal cleft fusion problems?
- Smoking
- alcohol abuse
- drugs - both medical and recreational
- viruses, rubella
- To much Vitamin A (or other retinoids)
- deficiencies in folic acid.
HA (hyaluronic acid) is made by 3 different enzymes what are they? What are the bigger and smaller ones?
Made by: HA synthase 1, HA synthase 2 and HA synthase 3.
Produce HA of different sizes. HA synthase 1 and 2 large molecular weight HA, HA synthase 3 smaller.
