Embryological Development of the Face

Introduction

• Speaker: Minas
• Topic: Embryological development of the face
• Objective: Simplify the understanding of embryology for beginners

Early Embryological Development

Blastula

• Ball of cells post-fertilization
• Travels down the uterine tube, implants into the uterine wall

Gastrulation

• Formation of three germ layers:
  • Ectoderm: Becomes skin and nervous system
  • Mesoderm: Develops into muscles, gonads, kidneys, connective tissue
  • Endoderm: Forms primitive gut

Folding Process

• Neural crest (blue) and neural tube form other structures
• Mesoderm differentiates into paraxial, intermediate, and lateral plates

Development of the Face

Week 4

• Development begins at the end of week 4
• Key structures:
  • Ototic placode, lens placode
  • Pharyngeal arches, heart bulge, umbilical cord
  • Neural tube, gut tube
• Neural crest cells move towards the front of the face, forming facial prominences

Facial Prominences

• Five facial prominences:
  • Frontonasal
  • Maxillary
  • Medial nasal (pair)
  • Lateral nasal (pair)
  • Mandibular
• Contribute to the formation of the face

Detailed Facial Development Week-by-Week

Week 5

• Nasal placodes form thickened ectoderm
• Nasal pits form as ectoderm invaginates
• Formation of medial and lateral nasal prominences

Week 6

• Tissue proliferation, maxillary prominences grow
• Nasolacrimal groove forms, connecting the medial eye to the nasal pit

Week 7

• Medial nasal prominences fuse with maxillary prominence
• Formation of upper lip, philtrum, and nasal structures

Key Structures and Contributions

• Frontonasal Prominence: Forehead, nose bridge
• Maxillary Prominence: Cheeks, lateral portion of upper lip
• Medial Nasal Prominence: Philtrum, nose crest and tip
• Lateral Nasal Prominence: Ala of the nose
• Mandibular Prominence: Lower lip, jaw

Formation of Intermaxillary Segment

• Formed from medial nasal prominence
• Components:
  • Labial: Philtrum
  • Upper Jaw: Includes four incisors
  • Palatal: Connective tissue plate (primary plate)

Palatine Shelf Development

• Growth of tissue forming palatine shelf
• Fusion forms the roof of the mouth, separates nasal cavity from mouth

Nasal and Oral Cavity Development

• Nasal Pit: Becomes the nostril, nasal cavity
• Oronasal Membrane: Degenerates, leading to nasal chamber
• Maxillary prominence contributes to secondary palate development

Paranasal Sinuses

• Contribute to facial shape & structure
• Grow until puberty, extend into maxilla, ethmoid, sphenoid, frontal bones

Conclusion

• Overview of facial embryological development
• Mention of upcoming topics: development of eyes and teeth

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