STRATIFIED SQUAMOUS EPITHELIUM – 1
Stratified epithelia are formed by more than one cell layer. The name of the stratified epithelia usually derives from the shape of the cells of their superficial layer.
The stratified squamous epithelium presented in the image is formed by several cell layers. An important feature of this epithelium is the following: the shapes of its cells are different in the various levels of the epithelial layer.
The cuboidal or polyhedrical basal cells form the deepest cell layers of this epithelium and they are supported by a basal lamina, as happens with other epithelia. Remember that when we use a light microscope, what we see supporting an epitelium is called a basal membrane, the association of a basal lamina with components of the extracellular matrix.
The basal cells divide and slowly migrate towards the surface. During cell migration, the cells change their synthesic patterns, produce new types of macromolecules and their shapes change becoming rounded and finally flattened.
The cells of the intermediary layers are elongated and the most superficial cells of this epithelium are flattened like plates or scales and for this reason they are called squamous cells.
The stratified squamous epithelium presented in the image is formed by several cell layers. An important feature of this epithelium is the following: the shapes of its cells are different in the various levels of the epithelial layer.
The cuboidal or polyhedrical basal cells form the deepest cell layers of this epithelium and they are supported by a basal lamina, as happens with other epithelia. Remember that when we use a light microscope, what we see supporting an epitelium is called a basal membrane, the association of a basal lamina with components of the extracellular matrix.
The basal cells divide and slowly migrate towards the surface. During cell migration, the cells change their synthesic patterns, produce new types of macromolecules and their shapes change becoming rounded and finally flattened.
The cells of the intermediary layers are elongated and the most superficial cells of this epithelium are flattened like plates or scales and for this reason they are called squamous cells.
In stratified squamous epithelia there is a continuous production of new cells in its basal portion and a continuous shedding of squamous cells of its surface.
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 greater in places exposed to greater forces.