ANATOMY&PHYSIOLOGY FOR NURSES

THE ELEMENTARY TISSUES OF THE BODY Four groups of tissue in the body are known as the elementary tissues. These are epithelial tissue, muscular tissue, nervous tissue,and connective tissue. Types of epithelial Tissue.     An epithelium consists of cells which cover surfaces of the body,  e.g skin; or line hollow organs, tubes or cavities, e.g. blood vessels, and the air cells. There are two main classes of epithelial tissue, each containing several varieties. all epithelial cells lie on and held together by a homogeneous substances called a basement membrane. Simple Epithelium. This class consists of a single layer of cells, and is subdivided into three varieties. Pavement or Squamous Epithelium. Pavement epithelial cells are fine thin plates placed edge to edge like the particles in a mosaic pattern or the stones of a pavement. These cells form the alveoli of the lungs. They are found whenever a very smooth surface is essential as in the lining of the heart, lining of blood vessels and lymphatics, the serous membranes. when lining these structures the epithelial covering or lining is called endothelium.      ............