Oral mucous membrane Dr Ehab Alsaih Assistant prof. Removable prosthodontics Dr Ehab Alsaih Assistant prof. Removable prosthodontics

Oral mucous membrane 1- Oral mucousa 2-Functional types of oral Mucosa

1- Oral mucousa

1.Oral Mucosa The moist lining of the oral cavity is called Oral Mucosa or Oral Mucous Membrane The function of oral mucosa is protection, sensation and secretion It is continuous with the skin outside the oral cavity and differs from it in appearance and structure Dr.Syed Sadatullah King Khalid University

Dr.Syed Sadatullah King Khalid University Oral Mucous Membrane

Dr.Syed Sadatullah King Khalid University Oral Mucous Membrane Epithelium Lamina Propria Submucosa Periosteum Bone

Oral Epithelium Oral epithelium forms the surface of the oral mucosa that forms a barrier between the oral environment and the deeper tissues It is derived from the embryonic ectoderm It is stratified squamous epithelium and may or may not be keratinized Beneath the epithelium lies the connective tissue Dr.Syed Sadatullah King Khalid University

Dr.Syed Sadatullah King Khalid University Oral Epithelium -Keratinized

Dr.Syed Sadatullah King Khalid University Keratinized oral epithelium Most of the oral mucosal surface is lined by nonkeratinized stratified squamous epithelium except gingiva, hard palate and dorsal surface of the tongue where the epithelium is keratinized The keratinized cells have no nuclei and the cytoplasm is displaced by large numbers of keratin filaments Keratinized epithelium is associated with masticatory function and have four layers of cells

Dr.Syed Sadatullah King Khalid University The four layers are: 1.Stratum Basale 2.Stratum Spinosum 3.Stratum Granulosum 4.Stratum Corneum Cellular layers of oral epithelium - Keratinized

1. Stratum Basale The cells of the stratum basale are cuboidal or low columnar and form a single layer resting on the basal lamina The basal lamina is at the interface of the epithelium and lamina propria Epithelial cells of the oral mucosa are in a constant state of renewal The basal cells show the maximum mitotic activity Dr.Syed Sadatullah King Khalid University

Dr.Syed Sadatullah King Khalid University 2.Stratum Spinosum Stratum spinosum is usually several cells thick They shaped like polyhedron with short cytoplasmic processes The stratum basale and the first layers of stratum spinosum are referred to as stratum germinativum because these cells give rise to new epithelial cells

3.Stratum Granulosum Cells of stratum granulosum are flat and are found in layers of three to five cells thick This layer is prominent in keratinized epithelium (and absent in nonkeratinized epithelium) These cells have keratohyaline granules in their cytoplasm Keratohyaline granules help to form the matrix of the keratin fibres found in the superficial layer Dr.Syed Sadatullah King Khalid University

4.Stratum Corneum Cells of stratum corneum are flat, devoid of nuclei and full of keratin filament surrounded by a matrix These cells are continuously being sloughed and are replaced by epithelial cells that migrate from the underlying layers Dr.Syed Sadatullah King Khalid University

Nonkeratinized oral epithelium Nonkeratinized epithelial cells in the superfecial layers do not have keratin filaments in the cytoplasm The surface cells also have nuclei The stratum corneum and stratum granulosum layers are absent This epithelium is associated with lining of the oral cavity Dr.Syed Sadatullah King Khalid University

Connective tissue Connective tissue can be differentiated as: Lamina Propria and Submucosa Lamina propria Lamina propria is the connective tissue layer immediately below the epithelium It can be divided into papillary layer and the reticular layer Papillary layer forms finger like projections of connective tissue that extend deep in the epithelial layers Dr.Syed Sadatullah King Khalid University

Oral Mucous Membrane Papillary layer is prominent in masticatory mucosa reticular layer is prominent in lining mucosa Lamina prorpria consists of: blood vessels and cells like fibroblasts cells of blood vessels and lymphatics and nerves Epithelium is avascular, hence its metabolic needs come via the vessels of the lamina propria Dr.Syed Sadatullah King Khalid University

Submucosa Submucosa lies below the lamina propria and serves as an attachment between lamina propria and bone or skeletal muscle It is found in the cheeks, lips and parts of the palate It consists of large blood vessels, nerves and lymphatics and its functions are nutrition and defense Dr.Syed Sadatullah King Khalid University