Stratified squamous epithelium

The corneal epithelium is a stratified squamous epithelium like the epidermis of the skin but is nonkeratinized like other mucosal epithelia such as the intestinal and airway epithelia. Although the corneal epithelium, five to seven cells thick, represents less than 10% of the entire corneal thickness, it provides as much as 99% resistance to the diffusion of small electrolytes such as Na+ and Cl [55-57],... 

The mouth is the region from the lips to the pharynx. The first step in the digestive process is chewing, or mastication, which is an initial mechanical breakdown of the food that facilitates its movement to the stomach. The mouth is lined with stratified squamous epithelium that provides extra protection from injury by coarse food materials. Three pairs of salivary glands secrete saliva into the oral cavity ... 

All rats survived dermal doses of up to 60 mg/rat administered over 13 weeks. Mean body weights were up to 14% lower than controls, and redness, scabs, and ulceration occurred at the application site. In mice, applications of up to lOmg/mouse produced increased liver and kidney weights. Compound-related skin lesions included sebaceous gland hyperplasia and hyperplasia and hyperkeratosis of the stratified squamous epithelium at the site of application ovarian atrophy was also considered to be compound related. 

Slaughter DP, Southwick HW, Smejkal W. Field cancerization in oral stratified squamous epithelium clinical implications of multicentric origin. Cancer 1953 6 963. 

The skin consists of two main compartments, the epidermis, a stratified squamous epithelium, and the underlying dermis, a richly vascularized tissue embedded in a connective tissue matrix (Fig. 41.1). The epidermis consists of multiple layers of keratinocytes, which differentiate into the outermost layer, the stratum corneum. This layer contains the hydrophilic structural... 

The lining of the vestibule, which contains a zone of short stiff hairs (vibrissae), acts as a baffle system for filtering out large (>10 pm) airborne particles. The stratified squamous epithelium of the vestibule is resistant to dehydration and inhaled irritants and poorly permeable. Between the vestibule and atrium, there is a constriction known as the internal... 

Makhno, T. et al. Expression of hornerin in stratified squamous epithelium in the mouse a comparative analysis with profilaggrin, J. Histochem. Cytochem., 51,485, 2003. 

The oral mucosa provides a protective covering for underlying tissues while acting as a barrier to the entry of microorganisms and toxins. Histologically, the stratified squamous epithelium lining the oral cavity exhibits a diverse structure as well as important inter-species differences. This... 

Cornea Stratified squamous epithelium Protects eye from injury... 

Mouth Stratified squamous epithelium Protects oral tissues... 

Skin Stratified squamous epithelium Protects body surface... 

Vagina Stratified squamous epithelium Protects internal surfaces... 

Mouth Posterior epithelium Stratified squamous Descemet s membrane Controls fluid transport... 

Epidermis Stratified squamous epithelium Stratum corneum Stratum spinosum Stratum basale Basement membrane Provides resistance to shear injury... 

The mouth and esophagus are composed of two layers, the mucosa and submucosa (Figure 3.5). The mucosa is lined on its outer surface by a stratified squamous epithelium with layers of polyhedral cells of the intermediate layers and low columnar cells of the basal layer. Below the cellular layer is the lamina propria containing loose connective tissue with blood vessels and small aggregates of lymphocytes. Smooth muscle within the mucosa (muscularis mucosal layer) is seen as small bundles. The submucosa... 

Skin is composed of two layers, the epidermis and dermis (Figure 3.7). The epidermis is a stratified squamous epithelium composed of a number of cell layers including the keratinized outer cell layer (stratum corneum),... 

Figure 3.7. Structure of skin. Skin is composed of two layers the dermis and epidermis. Epidermis is a stratified squamous epithelium containing stratum corneum, stratum spinosum, and stratum basale (basal cell layer). The dermis contains papillary and reticular layers and a subcutaneous layer containing fat, blood vessels, and skeletal muscle.

The epithelium of the mouth consists of stratified, squamous epithelium, which can be keratinized, or non-keratinized. 

The upper respiratory tract, particularly the nose, has a unique anatomy that performs normal physiologic functions as well as innate defense against inhaled toxicants. The nose extends from the nostrils to the pharynx. Inspired air enters the nose through the nostrils. The nasal cavity is divided longitudinally by a septum into two nasal compartments. In most mammalian species, each nasal cavity is divided into a dorsal, ventral, and middle (lateral) meatus by two turbinate bones, the nasoturbinate and maxilloturbinate. These turbinates project from the dorsolateral and ventrolateral wall of the cavity, respectively. In the posterior portion of the nose, the ethmoid recess contains the ethmoturbinate. The nasal cavity is lined by a vascular mucosa that consists of four distinct types of epithelia. In rodents, these epithelia are (1) the stratified squamous epithelium that lines the nasal vestibule and the floor of the ventral meatus in the anterior portion of the nose (2) the non-ciliated, pseudostratified, transitional epithelium that lies between the squamous epithelium and the respiratory epithelium and lines the lateral meatus (3) the ciliated respiratory epithelium that lines the remainder of the nasal cavity anterior and ventral to the olfactory epithelium and (4) the olfactory epithelium (neuroepithelium) that lines the dorsal meatus and ethmoturbinates in the caudal portion of the nose. The relative abundance and exact locations of these upper respiratory epithelium differ among mammalian species. 

FIGURE 2 Detail of human vaginal mucosa of fertile adult (H E, x40). Image shows stratified squamous epithelium (E), which is nonkeratinized, and lamina propria (LP), richly supplied by small blood vessels and deprived of glands (Courtesy of Manuel Dias.)... 

The conjunctiva proceeds onto the globe from the fornix to form the bulbar conjunctiva, which overlies Tenon s capsule and merges with the limbal cornea. Loosely attached to the capsule over the entire globe, the bulbar conjunctiva forms a homogeneous layer of stratified squamous epithelium at the limbus and contains many goblet... 

Oral mucosae are composed of multiple layers of cells, which show various patterns of differentiation dependent on the functions of different regions in the oral cavity. The oral mucosa is covered by a stratified, squamous epithelium, and three different types of mucosa can be distinguished the masticatory, the lining, and the specialized mucosa. Blood supply to the oral cavity tissues is delivered via the external carotid artery, which branches to the maxiliary lingual and facial artery. There are no mucus-secreting goblet cells in the oral mucosa, but mucins are found in human saliva. These mucins are water-soluble and form a gel of 10-200 pm thickness. Saliva, mainly composed of water (99%), is continuously secreted in the oral cavity and exists as a film with a thickness of 0.07-0.1 mm. ... 

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