Epithilium vs Endothelium | Endothelium vs Epithilium Tissues
A tissue is a group of physically linked cells with associated intercellular substances, which are specialized in a particular function or functions. The animal body is composed of four fundamental types of tissues on the basis of their structure and functions. These are epithelial tissue, connective tissue, muscular tissue and nervous tissue. The epithelial tissue is the covering of all external and internal body surfaces. It lines whole external surface of the skin, internal cavities and lumens as well as the external and internal surfaces of the vessels. They also help the exocrine function by the formation of glands. The external epithelium is called the exothelium, it is the epithelium that covers the skin and organ lining. There are also two sub types of the epithelium: mesoderm that lines internal cavities and lumens and the mesothelium that covers vessels and the heart chambers. Hence, essentially the endothelium is part of the epithiliual tissue which helps the body protect itself from damages.
The endothelium is a specialized type of epithilium found in the lining of blood and lymphatic vessels. It also lines the heart cavities. This tissue has an embryonic mesodermal origin. It usually helps a smooth flow of fluid upon its surface. It is composed of flattened cells adhered to a basal membrane with elastin fibers running through it. This gives the endothelium a distensible quality and the ability to accommodate the fluctuating flow of fluid. The endothelial cells form a sheet like barrier to regulate the entry of external material, microorganisms and toxins, as well as fluid flow in and out of the vessels. They are sensitive to blood pressure and secrete vasodilators such as prostacylin and Nitric oxide in response to a high blood pressure. At an event of damage to the blood vessel, the endothelium secrets thromboplastin; this helps the coagulation of blood and responds to cytokinase to increases the permeability to white blood cells.
The epithelium is made up of cells that are closely packed and arranged in one or more layer. True epithelial tissue has an ectodermal and endodermal embryonic origin. This tissue is avascular hence the adjoining connective tissue supplies it with food nutrients and energy through simple diffusion. For that, the basal membrane is perforated by blood and lymph vessels and nerve endings for sense. These provide the functions of protection from mechanical physiological and microbial damage, secretary function of enzymes, hormones and lubricating fluids by the glandular epithelium and sensory function through the nerve endings.
What is the difference between epithilium and endothelium tissues?
In comparing the two types of tissues, epithelium and endothelium, it could be said that their basic functionality is similar as in the secretary, protective and sensory functions. However, they have a different embryonic origin with epithelium having an ectodermal and endodermal origin and endothelium having a mesodermal origin. The basal membrane of the epithelium has keratin fibers associated, and endothelium has elastin fiber associated basal membrane. They both have a high generative and healing capacity. Furthermore, the endothelium secretes substances involved in the blood coagulation and white blood cell stimulation, which are not functions of the epithelial tissues. However, they secrete enzymes, hormones and lubricating fluids and help clean surfaces through the action of microvilli which are absent in the endothelial tissue. In the epithelial tissue, the factors are secreted by the associated gland or mucosa secreting cells. But the sqauomose flattened cells themselves do the secretion in the endothelial tissue. The endothelium is composed of a single live cell layer, whereas the epithelium may have multiple layers of cells, which can be alive or dead. Hence, essentially the endothelium and the epithelium are tissues with the same function, each modified to suit its environment and function.