STRATIFIED SQUAMOUS EPITHELIUM – 1
Stratified epithelia are formed by more than one cell layer. They are usually named according to the shape of their most superficial cell layer.
The stratified squamous epithelium exhibited in the image is formed by several cell layers. An interesting and important feature of this epithelium: the shapes of its cells differ in the various levels of the layer.
The cuboidal or polyhedrical basal cells form the deepest cell layer and are supported by a basal lamina, as happens with other epithelia. Remember that when we use a light microscope, what we see immediately supporting an epitelium is called a basal membrane, the association of the basal lamina with components of the extracellular matrix of the underlying connective tissue.
The basal cells divide by mitosis and slowly migrate toward the epithelial surface. During their migration, the cells change their synthesic patterns, produce new types of macromolecules and become round, then elongated and finally flattened. The most superficial cells are flattened as plates or scales and are called squamous cells.
Most stratified squamous epithelia undergo a continuous production of new cells (by mitosis) in its basal portion and a continuous shedding of superficial squamous cells.
This type of epithelium is usually found in places subject to friction or mechanical forces, such as the oral cavity, esophagus, and vagina. The thickness of this epithelium, wich reflects the number of cell layers, is usually larger in places exposed to greater attrition.
The stratified squamous epithelium exhibited in the image is formed by several cell layers. An interesting and important feature of this epithelium: the shapes of its cells differ in the various levels of the layer.
The cuboidal or polyhedrical basal cells form the deepest cell layer and are supported by a basal lamina, as happens with other epithelia. Remember that when we use a light microscope, what we see immediately supporting an epitelium is called a basal membrane, the association of the basal lamina with components of the extracellular matrix of the underlying connective tissue.
The basal cells divide by mitosis and slowly migrate toward the epithelial surface. During their migration, the cells change their synthesic patterns, produce new types of macromolecules and become round, then elongated and finally flattened. The most superficial cells are flattened as plates or scales and are called squamous cells.
Most stratified squamous epithelia undergo a continuous production of new cells (by mitosis) in its basal portion and a continuous shedding of superficial squamous cells.
This type of epithelium is usually found in places subject to friction or mechanical forces, such as the oral cavity, esophagus, and vagina. The thickness of this epithelium, wich reflects the number of cell layers, is usually larger in places exposed to greater attrition.
