What type of epithelium is found in the mouth?
The lining mucosa of the oral cavity, which is present on the lips, buccal mucosa, alveolar mucosa, soft palate, underside of the tongue, and floor of the mouth, has an epithelium that is usually non-keratinized (Fig. 3.1C).
What type of tissue is the oral cavity lined with?
The oral cavity is lined by a mucous membrane (the oral mucosa) consisting of a stratified squamous epithelium, which may or may not be keratinized, and an underlying connective tissue layer, the lamina propria.
What is oral mucosa made up of?
Histologically, the oral mucosa is formed by three layers, a surface squamous stratified epithelium, known as the oral epithelium, whose thickness and degree of keratinization depend on the location and functional requirements [1].
How does oral epithelium maintain its structural integrity?
The oral epithelium, like other covering and lining epithelia, maintains its structural integrity by a process of continuous cell renewal in which cells produced by mitotic divisions in the deepest layers migrate to the surface to replace those that are shed (Nakamura et al., 2007).
Which type of epithelial tissue forms the lining of the oral cavity esophagus?
stratifying squamous epitheliumThe soft tissues of the human oral cavity and esophagus are covered everywhere by a stratifying squamous epithelium (1). In regions subject to mechanical forces associated with mastication (i.e., the gingiva and hard palate) there is a keratinizing epithelium resembling that of the epidermis covering the skin.
What type of epithelium is found in the oral cavity and pharynx?
stratified squamousThe oral pharynx is lined by a stratified squamous non-keratinizing type of epithelium and lacks both muscularis mucosae and submucosa.
Which tissue type is found in the lining of the oral cavity quizlet?
Oral mucosa almost continuously lines the oral cavity. Microscopically oral mucosa is composed of stratified squamous epithelium overlying a connective tissue proper, or lamina propria, with possibly a deeper submucosa.
What is the oral cavity lined with?
The mucous membrane that lines the structures within the oral cavity limits is known as oral mucosa. This is a wet soft tissue membrane that extends from the junction between the vermilion border of the lips and labial mucosa anteriorly to the palatopharyngeal folds posteriorly.
Where is stratified squamous epithelium found?
The outer layer of your skin (the epidermis) is made of stratified squamous epithelial cells. Stratified cuboidal epithelium: This type of epithelium is not as common and is found in the excretory ducts of your salivary and sweat glands.
Where is simple squamous epithelium found?
Simple squamous epithelia are found lining the cavities of the body including the pericardial, pleural, and peritoneal cavities, or in areas where passive diffusion occurs, such as glomeruli in the kidney and alveoli in the respiratory tract.
What is a stratified squamous epithelium?
Stratified squamous epithelium consists of a single basal layer containing stem cells, 2–3 layers of proliferative basaloid cells in the suprabasal region, and larger keratinized cells toward the surface. The esophageal squamous epithelium is nonkeratinizing, i.e., it does not have a stratum corneum.
How many types of stratified squamous epithelium are found within the oral cavity?
Three typesThree types of stratified squamous epithelium are found within the oral cavity: nonkeratinized, orthokeratinized, and parakeratinized (Table 9-2).
What tissue is found in the pharynx?
The pharynx is composed of mucous membrane, submucosal connective tissue, glands, lymphoid tissue, muscle and an outermost adventitial coating. The mucous membrane does not possess a muscular layer.
Is the oral cavity Keratinized?
Oral gingival epithelium is keratinized while the sulcular and junctional epithelia (JE) as well as the lining mucosa are not keratinized (14).
What is oral epithelium?
The oral mucosal epithelium is a barrier that separates the underlying tissues from their environment. It consists of two layers, the surface stratified squamous epithelium and the deeper lamina propria.
Where is Parakeratinized epithelium found?
oral cavityThe parakeratinized epithelium is a common and widespread type of keratinized epithelium in the oral cavity in adult birds. In contrast to orthokeratinized epithelium, which mostly covers mechanical papillae and the lingual nail, parakeratinized epithelium covers almost the entire dorsal surface of the tongue in birds.
What are the layers of the oral epithelium?
Four layers form the oral epithelium in keratinized oral mucosa, which is the case of the masticatory mucosa. Commencing from the deeper layer, we found the stratum basale followed by stratum spinosum, stratum granulosum, and stratum corneum. When the epithelium is nonkeratinized, such as in the lining mucosa, above the stratum basale, there is a stratum filamentosum and stratum distendum [1]. Moreover, the non-keratinized epithelium, seen on the lining mucosa, lacks the granular layer, and the spinous layer is known to be generally thinner [5]. The cells that form the epithelium are attached to each other by desmosomes and get gradually flatten from the stratum basale upwards to the stratum corneum, where they acquired a scaly or squamous appearance. Squamous epithelial cells are known as keratinocytes since they are mostly composed of cytokeratins.
Which cells reside in the oral epithelium?
Besides keratinocytes, other specialized cells permanently reside within the oral epithelium, referred to as non-keratinocyte cells, including melanocytes, Langerhan cells, and Merkel cells. Moreover, other various inflammatory cells may transiently migrate to the oral epithelium.
What are the three types of mucosa?
The oral mucosa can be classified into three types that differ histologically, clinically, and functional ly. The mucosa that lines the mobile structures of the mouth receives the name of lining, ormoveable mucosa, which is found on the soft palate, cheeks, lips, alveolar mucosa, the floor of the mouth, and vestibular fornix. The type of epithelium that covers the lining mucosa is a non-keratinizedstratified squamous epithelium [1]. The rigid mucosa tightly bound to the underlying bone in the attached gingiva and hard palate is known as masticatory mucosa. The type of epithelium covering these surfaces is a keratinized or para-keratinizedstratified squamous epithelium, which provides the masticatory mucosa its capacity to better support the stress upon which it is subjected during mastication. Finally, there is a specialized mucosa on the dorsum of the tongue that shows a squamous stratified epithelium that can be either keratinizedor non-keratinized. It receives this name because of its unique feature of having different types of lingual papillae and taste buds that allow taste perception. Because the dorsum of the tongue actively participates in mastication, this mucosa is sometimes also classified as masticatory mucosa.
What is the oral mucosa?
The oral mucosa can be classified into lining mucosa, masticatory mucosa, and specialized mucosa, with distinctive histological, clinical, and functional features. The variety of functions that the oral mucosa develops mainly includes protecting the underlying tissues from mechanical, chemical, and biological stimuli, secretion of essential substances, and a sensory function, which allows the perception of temperature, touch, pain, and taste [2][3][4][2].
How many layers are there in the oral mucosa?
Histologically, the oral mucosa is formed by three layers, a surface squamous stratified epithelium, known as the oral epithelium, whose thickness and degree of keratinization depend on the location and functional requirements [1]. Beneath is an underlying connective tissue, known as lamina propria, and a dense irregular connective tissue, the submucosa, which is found at the deepest level. The latter is absent in some oral cavity regions, where the lamina propria is directly bound to the bone or muscle.
What is the surface of the oral mucosa?
The entire surface of the oral mucosa is covered by squamous stratified epithelium. This is a highly organized, avascular, and semipermeable tissue whose thickness and degree of keratinization varies according to the location in the oral cavity and the area's functional and mechanical requirements. An interdigitated interface connects the epithelium and the lamina propria. The undulating projections of the deeper layer of the epithelium, known as rete pegs, attach to the underlying papillary projections of the lamina propria. Between these two tissues, there is a non-cellular basement membrane to which the epithelium is tightly bound. The basement membrane provides support to the epithelium and connects them to the connective tissue. On light microscopy, it is seen as a line of demarcation between the epithelium and connective tissue of the lamina propria. However, it is better observed with electron microscopy that clearly shows the basal lamina, which is further subdivided into lamina lucida and lamina densa.
Where is the submucosa located?
The submucosa is found in all the buccal cavity regions except the attached gingiva and the hard palate covered by masticatory mucosa , where the submucosa layer is absent, and the lamina propria is directly attached to the underlying bone, forming a mucoperiosteum.
What is the oral cavity made of?
The oral cavity is lined by a mucous membrane (the oral mucosa) consisting of a stratified squamous epithelium, which may or may not be keratinized, and an underlying connective tissue layer, the lamina propria. The surface is kept moist with mucus produced by the major and numerous minor salivary glands.
What is the stratified squamous epithelium?
A stratified squamous non-keratinized epithelium lines the oral surface of the lips, cheeks, floor of mouth, and covers the ventral surface of the tongue In slide 114 (human) and 114M (monkey) of the lip, note that skin (stratified, keratinized squamous epithelium with hair follicles) covers the external surface View Image, skeletal muscle (orbicularis oris muscle) forms the core View Image, and a mucosal epithelium (stratified, non-keratinizing squamous epithelium) covers the internal surface View Image. A lamina propria underlies the mucosa and small salivary glands (labial salivary glands) View Image are present in the submucosa. Note the transition zone between the keratinized epithelium of the skin and the nonkeratinized epithelium of the mucosa. This transition zone is called the vermillion zone (present only in humans) View Image. In the transition zone, long connective tissue papillae extend deep into the epithelium. Capillaries are carried close to the surface in these papillae. Because the epithelium is very thin in this region, the lips appear red (this arrangement may or may not be apparent in your glass slides). Salivary glands are lacking in the vermillion zone, therefore, the lips must be continuously moistened (by the tongue) to prevent drying out.
What are the papillae in Slide 117?
Slide 117 and especially slide 117N contain examples of circumvallate papillae View Image. These are large circular papillae surrounded by a deep trench. The covering epithelium is non-keratinized. Taste buds View Image, the chemoreceptors for the sense of taste, are located on the lateral borders. Each taste bud contains about 50 spindle shaped cells that are classically described based on their appearance as “light” (receptor) cells, “dark” (supporting) cells, and “basal” (stem) cells, although these distinctions are difficult to see in your slides so we do not require you to identify the cell types. Non-myelinated nerves from cranial nerves VII, IX, or X (depending on the location of the taste bud) synapse with the receptor and, to some extent, supporting cells of the taste bud. Some slides show serous glands (of von Ebner) View Image in the lamina propria and interspersed between the bundles of muscle beneath the papillae. These glands drain into the base of the trench around the circumvallate papillae.
What are the two types of papillae on the tongue?
In slide 116 there are two types of papillae on the tongue. Locate the numerous filiform papilla e View Image, that appear as conical structures with a core of lamina propria covered by a keratinized epithelium. Fungiform papillae View Image are scattered among the filiform papillae. They have expanded smooth round tops and narrower bases. In young children, the fungiform papillae can be seen with the naked eye as red spots on the dorsum of the tongue (because the non-keratinized epithelium is relatively translucent). These papillae are less readily observed in adults, because of slight keratinization of the epithelium.
Why are there red spots on my tongue?
In young children, the fungiform papillae can be seen with the naked eye as red spots on the dorsum of the tongue (because the non-keratinized epithelium is relatively translucent). These papillae are less readily observed in adults, because of slight keratinization of the epithelium.
Why does the tooth in the mandible lack enamel?
2. Tooth. The tooth in these sections lacks its outer layer of enamel because the tissue has been decalcified (recall that enamel is ~95% mineral); however, the matrix of the dentin is well preserved as is the cementum and adjacent matrix of the alveolar bone of the mandible.
Where is the stratified squamous keratinized epithelium located?
A stratified squamous keratinized epithelium is found on surfaces subject to the abrasion that occurs with mastication, e.g., the roof of the mouth (palate) and gums (gingiva). Slide 115, which you used to study bone and the respiratory system, is a longitudinal section through the palate and includes the lip, gingiva, hard palate, and a portion of the soft palate [orientation]. This tissue is from a term fetus (with unerrupted teeth) and the epithelium over the hard palate is not yet fully differentiated (i.e. not fully keratinized). The slide is, however, a good overall orientation to the histology of the hard and soft palate. In the adult the epithelium of the hard palate is keratinized. Identify respiratory epithelium, bone (hard palate), forming tooth View Image, and skeletal muscle in the lip View Image and the soft palate View Image. Some slides show mucous salivary glands View Image in the submucosa.