What is the shape of a squamous cell?
The billions of human body cells are specialized for particular functions. Groups of cells that are similar in structure and function are called tissues. The four primary tissue types and their basic function are: epithelial (covering), connective (support), muscle (movement), and nervous (control). Epithelial tissues form the covering of all body surfaces, line body cavities and hollow organs, and are the major tissue in glands. They perform a variety of functions that include protection, secretion, absorption, excretion, filtration, and sensory reception. Epithelial tissues have some special characteristics: • The cells fit closely together to form continuous sheets. • The membranes always have one surface or edge that is unattached to other cells. This apical surface is exposed to the body’s exterior or to the cavity of an internal organ. • The lower surface of the tissue rests on a basement membrane, a structureless material secreted by the cells. • Epithelial tissues have no blood
