Mucosa of mouth

Tunica mucosa oris

Synonym: Mucous membrane of mouth; Oral mucosa

Antoine Micheau

The mucosa of mouth (Oral mucosa) is the moist tissue lining the inner surface of the oral cavity. It is composed of two main layers: a stratified squamous epithelium and an underlying connective tissue layer (lamina propria), separated by a basement membrane. Beneath the lamina propria, a deeper layer called the submucosa containing glands, nerves, and adipose tissue attaches the mucosa to the underlying bone or muscle.

Types of Oral Mucosa

The oral mucosa is classified into three functional types based on its histological features and location:

Lining mucosa: Covers the lips, cheeks, floor of the mouth, ventral tongue, and soft palate. It has a non-keratinized epithelium and a flexible, mobile connective tissue. This type accounts for the majority of the oral mucosal surface.
Masticatory mucosa: Found on the gingiva and hard palate areas subjected to strong mechanical forces during chewing. It has a keratinized epithelium and a dense, firmly attached connective tissue (collagenous lamina propria) bound tightly to the underlying periosteum.
Specialized mucosa: Located on the dorsal surface of the tongue, containing papillae (filiform, fungiform, circumvallate, and foliate) and taste buds, serving both masticatory and sensory functions.

Functions

The oral mucosa serves as a critical barrier protecting underlying tissues from mechanical damage, microbial invasion, and entry of toxic substances. It also participates in regulation of water and electrolyte balance, thermoregulation, and initiation of immunological functions. A salivary film (approximately 70100 μm thick) overlying the epithelium provides additional protection through mucins, defensins, immunoglobulins, lysozyme, and other antimicrobial proteins.

The boundary between masticatory and lining mucosa is marked by the mucogingival junction, a clinically important landmark in periodontal and implant surgery.

Key structures of mucosa of mouth