The Various Types of Epithelium
Epithelium tissue is one of the four basic tissue types. The boundary between you and the external world is marked by a continuous surface, or epithelium, of contiguous cells. The importance of Epithelium tissue serves both as a protective barrier to the body and as an active interface with the environment. The structural and functional integrity of this epithelium is vital to the overall normal health of the organism.
There are several features such as, differences in cell shape and cell orientation that characterize epithelial tissue and distinguishes it from the other three tissue types. Epithelial tissue is divided into eight sub categories; ...view middle of the document...
Simple Cuboidal Epithelium cells are a single layer of cube-like cells with large, spherical central nuclei. The function of these particular cells involve secretion and absorption. Simple Cuboidal Epithelium cells are located in the Kidney tubules; ducts and secretory portions of small glands and the surface of the ovary.
Simple Columnar Epithelium cells consists of a single layer of cells that are tall in length with round to oval nuclei. The layer of the cells may contain goblet cells. The function of these particular cells consist of absorption; secretion of mucus, enzymes; the reproductive cells are ciliated and propel mucus by ciliary action. The non-ciliated Simple Columnar Epithelium cells are located in the lining of the stomach to anal canal(digestive tract), gallbladder, and excretory ducts of certain glands. Simple Columnar Epithelium cells that are ciliated are located in the lining of small bronchi, uterine tubes, and certain regions of the uterus.
Pseudostratified Ciliated Columnar cells consists of a single layer of cells that have various heights. Some of the cells reach the free surface while others do not. The nucleus of these particular cells are seen at different levels. Pseudostratified Ciliated Columnar cells may also contain cilia and goblet cells which secrete a mucus like substance.
Stratified Squamous Epithelium cells are composed of several cell layers. The basal cells are cuboidal and/or columnar; the surface cells consist of squamous cells. In Stratified Squamous Epithelium cells that contain keratin, the surface cells contain huge amounts of keratin and are dead. The basal cells of this particular cell that contains keratin are alive and produce the cells of the superficial layers. The function of these particular cells aid in protecting the underlying tissues in areas that are more prone to abrasion. The location of these cells depend on whether they contain keratin or are nonkeratinized. Keratinized cells form the the epidermis of the skin and non-keratinized cells form the linings of areas that are moist. Examples of these include, the esophagus, mouth, and vagina, urethra and anus.
Stratified Cuboidal Epithelium cells consist of two layers of cubelike cells. The function...