BIOL 1215 Lecture Notes - Basement Membrane, Epithelium, Free Surface
Document Summary
Consists of cells arranged in continuous sheets, in either single or multiple layers. Closely packed and held tightly together by many cell junctions, there is little intercellular space between adjacent plasma membranes. Form covering and lining of the body. It is never covered by another tissue, so it always has a free surface. 3 major functions: selective barrier that regulates the movement of materials in and out of the body, secretory surfaces that release products produced by cells onto their free surface. 3 . protective surfaces resist abrasive influences of environment. Surfaces of epithelial cells differ in structure and have specialized functions. Faces the body surface, body cavity, lumen (interior space) of internal organs, or duct. Opposite of apical layer and adhere to extracellular materials. Thin double extracellular layer that serves as the point of attachment and support for overlying epithelial tissue: basal lamina. Closer to and secreted by the epithelial cells.
