Function[ edit ] Elastase breaks down elastinan elastic fibre that, together with collagendetermines the mechanical properties of connective tissue. Elastase also has the important immunological role of breaking down Shigella virulence factors. This is accomplished through the cleavage of peptide bonds in the target proteins. The specific peptide bonds cleaved are those on the carboxyl side of small, hydrophobic amino acids such as glycinealanineand valine.
In general, epithelial tissues are classified by the number of their layers and by the shape and function of the cells. Squamous epithelium has cells that are wider than their height flat and scale-like.
This is found as the lining of the mouthoesophagus the blood vessels and in the alveou of the lungs. Cuboidal epithelium has cells whose height and width are approximately the same cube shaped.
Columnar epithelium has cells taller than they are wide column-shaped.
By layer, epithelium is classed as either simple epithelium, only one cell thick unilayered or stratified epithelium as stratified squamous epitheliumstratified cuboidal epitheliumand stratified columnar epithelium that are two or more cells thick multi-layered  and both types of layering can be made up of any of the cell shapes.
This kind of epithelium is therefore described as pseudostratified columnar epithelium. In general, it is found where absorption and filtration occur. The thinness of the epithelial barrier facilitates these processes.
The four major classes of simple epithelium are: Non-ciliated epithelium can also possess microvilli. Some tissues contain goblet cells and are referred to as simple glandular columnar epithelium.
The ciliated type is also called respiratory epithelium as it is almost exclusively confined to the larger respiratory airways of the nasal cavity, trachea and bronchi.
Stratified epithelium[ edit ] Stratified epithelium differs from simple epithelium in that it is multilayered. 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.
Cells flatten as the layers become more apical, though in their most basal layers the cells can be squamous, cuboidal or columnar.
This specialization makes the epithelium waterproof, so is found in the mammalian skin.
The lining of the esophagus is an example of a non-keratinized or "moist" stratified epithelium. These nuclei are pyknoticmeaning that they are highly condensed. Parakeratinized epithelium is sometimes found in the oral mucosa and in the upper regions of the esophagus.
It is sometimes called urothelium since it is almost exclusively found in the bladder, ureters and urethra. Type Description Squamous Squamous cells have the appearance of thin, flat plates that can look polygonal when viewed from above. The cells fit closely together in tissues; providing a smooth, low-friction surface over which fluids can move easily.
The shape of the nucleus usually corresponds to the cell form and helps to identify the type of epithelium. Squamous cells tend to have horizontally flattened, nearly oval shaped nuclei because of the thin flattened form of the cell.
Squamous epithelium is found lining surfaces such as the skinand alveoli in the lungenabling simple passive diffusion as also found in the alveolar epithelium in the lungs.
Specialized squamous epithelium also forms the lining of cavities such as in blood vessels, as endothelium and in the pericardiumas mesothelium and in other body cavities.REVIEW SHEET Classification of Tissues 6exerciseA Review Sheet 6A Tissue Structure and Function—General Review 1.
Define tissue: 2. Use the key choices . Definition, functions, physiological and chemical classification of carbohydrates. Monosaccarides or simply sugars, oligosaccharides, polysaccharides. Epithelium (/ ˌ ɛ p ɪ ˈ θ iː l i ə m /) is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous arteensevilla.comlial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs.
An example is the epidermis, the outermost layer of the skin. Classification of Tissues 6exerciseA Protection, support, and the binding together of other body tissues. Living cells are soft and fragile.
The large amount of non-living matrix (containing fibers) seen provides the strength needed for the normal functions of connective tissues. The classification of medical devices rules along with regulatory approval and registration by the CDSCO is under the control of Drug Controller General of India (DCGI).
All medical devices in India follow a regulatory framework that is based on the drug regulations under the Drugs and Cosmetic Act () and Drugs and Cosmetic Rules . 1 Classification of Malocclusion Dr.
Robert Gallois REFERENCE: ESSENTIALS FOR ORTHODONTIC PRACTICE By Riolo and Avery Chapter 6 .