Characteristics of epithelial tissue
These sheets are held together by specialized junctions. Simple Columnar Simple columnar epithelium is a single row of tall, closely packed cells, aligned in a row.
Epithelial tissue examples
Stratified epithelia are more durable and protection is one their major functions. Type Description Squamous Squamous cells have the appearance of thin, flat plates that can look polygonal when viewed from above. It is therefore found where body linings have to withstand mechanical or chemical insult such that layers can be abraded and lost without exposing subepithelial layers. Columnar epithelium has cells taller than they are wide. By layer, epithelium is classed as either simple epithelium, only one cell thick unilayered or stratified epithelium having two or more cells in thickness or multi-layered — as stratified squamous epithelium , stratified cuboidal epithelium , and stratified columnar epithelium ,   and both types of layering can be made up of any of the cell shapes. Epithelium also serves as glandular epithelium. These nuclei are pyknotic , meaning that they are highly condensed. Intercellular spaces in epithelium are small. Less visible but equally important is the localization of membrane proteins, which confer special properties to the membrane i. An epithelium has a free surface, the apical surface, exposed to the outside, and an attached surface, the basal surface, resting on the underlying connective tissue.
Transitional Epithelia Transitional epithelia are found in tissues that stretch and it can appear to be stratified cuboidal when the tissue is not stretched, or stratified squamous when the organ is distended and the tissue stretches.
However, it can also have the following specializations: Keratinized Epithelia In keratinized epithelia, the most apical layers exterior of cells are dead and lose their nucleus and cytoplasm. Pseudostratified epithelium possesses fine hair-like extensions called cilia and unicellular glands called goblet cells that secrete mucus.
The germinal epithelium that covers the female ovaryand the germinal epithelium that lines the walls of the seminferous tubules in the testes are also of the cuboidal type. Squamous epithelium: Latin, squama- scale flat, thin, scale-like cells, eg.
Epithelial tissue has a really rich nerve supply, this is really important because these nerves gather really important sensory information such as pressure, pain and temperature, by being able to detect all of these sensations it can actually stop us from hurting ourselves.
based on 75 review