Recording-2025-02-20T17_00_09.111Z

Development of the Oral Mucosa

• Initial Stages

  • Begins as a small indentation of epithelium derived from the exome.

  • Occurs around 3 to 4 months of embryonic development.

  • Single-layer epithelial cells divide into two layers:

    • Dental Lamina: Continues to form during ontogenesis.

    • Vestibular Lamina: Gives rise to the oral mucosa.

Morphological Divisions

• Division of the Structure:

  • Divides into anterior and posterior parts.

  • Tuberculum Impar:

    • A small round structure from the first pharyngeal arch that grows and gives rise to parts of the anterior tongue and mucosa.

  • Lateral Lingual Swellings:

    • Grow lateral to the tuberculum impar, contributing to the anterior two-thirds of the tongue.

Posterior Structures

• Copula and Hypoglossal Eminence:

  • Medial to pharyngeal arches 2 and 4.

  • Copula: Smaller structure involved in forming posterior third of oral mucosa.

  • Hypoglossal Eminence: Larger structure that also contributes to posterior third of the tongue.

  • Arises primarily from the vestibular lamina during weeks 5 and 6.

Timeline of Development

• Week 4: Formation of the stomodium (primitive oral cavity); single layer of epithelial cells.

• Weeks 5 and 6: Division of epithelial cells into dental and vestibular laminae, leading to tongue morphogenesis.

  • Separation of lips and cheeks from the mucosa around weeks 11 to 14.

  • Ectodermal proliferation continues until week 23.

Characteristics at Birth

• Newborn oral mucosa is delicate, thin, and contains basic structures resembling adult mucosa but primarily nonkeratinized.

  • Kinization is minimal; keratinization primarily in the gums and hard palate.

  • Increased susceptibility to infections due to underdeveloped natural microbiome and immature salivary glands (developing around 6-7 months) leading to limited saliva production.

  • At Birth: Oral mucosa appears smooth, pink, moist, and shiny.

Changes During Growth

• Continual Maturation:

  • Oral mucosa matures throughout childhood and adolescence.

  • Epithelial thickness increases and becomes more keratinized in areas subjected to wear (e.g. hard palate, gingiva).

  • Connective tissue becomes denser and more organized.

  • Development of taste buds in the tongue can affect eating preferences (picky eating behaviors may emerge during this transition).

Functions of the Oral Mucosa

• Protection:

  • Main function; protects deeper tissues from mechanical and bacterial injury.

• Sensation:

  • Contains receptors for temperature, touch, and pain, including taste buds which are developed to respond to specific stimuli (thirst, water).

• Reflexes:

  • Includes critical reflex actions such as swallowing, gagging, and salivating, all initiated by oral mucosa receptors.