Stratified squamous epithelium – this is the most common stratified epithelium in the body which consists of several layers of cells. Cells located at the outer portion or edge area are squamous cells while those that are located near the basement are either cuboidal or columnar. This type of epithelium is located in sites where a good deal of abuse or friction is occurring in the body. These areas are the esophagus, mouth and the outer portion of the skin.
Stratified columnar epithelium – in this type of stratified epithelium the cells are columnar. However the basal cells are in various sizes and shapes. This is a rare epithelium in the body where it is just found in the ducts of the large glands.
Stratified cuboidal epithelium – like the stratified columnar epithelium these cells are also rare in the body and are only found in the ducts of the large glands in the body. Typically, this type of stratified epithelium has at least two layers of cells with the surface cells becoming cuboidal in shape.
Transitional epithelium – this epithelium forms the lining of few organs such as the urinary bladder, the ureters and part of the urethra. With a transitional epithelium, cells located at the base are either cuboidal or columnar while those at the free surface are varying in their appearance. Thus, it is a highly modified and stratified squamous epithelium. The transitional cells has the ability of stretching by sliding past one another and changing their shape thus allowing stretching of the organ to take place.
The main function of glandular epithelium is for secretion. A gland is composed of one or more cells that makes and secretes a particular product or secretion. This secretion contains molecules in a water based fluid. Two glands in the body are developed from the epithelial sheets namely:
- Endocrine glands – these are the ductless glands which secrete hormones that directly diffuse into the blood that intertwines through the glands. Endocrine glands include the thyroid, adrenals and the pituitary.
- Exocrine glands – are the glands that carry out their function of secretion through their ducts to the epithelial surface. Included in this classification are the sweat and oil glands, the liver and the pancreas.
Connective tissues are located everywhere in the body. Based on its name, it is responsible for connecting body parts. The functions of these tissues are the mainly the following:
- Binding together other body tissues
image from eoearth.org
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