There are four main types of tissues in the body: epithelial, connective, muscular, and nervous tissue. Epithelial tissue lines body cavities and organs. It is composed of cells and can be simple with one cell layer or stratified with multiple cell layers. Connective tissue binds, protects, insulates, and transports throughout the body. It includes bone, blood, cartilage and different types of connective tissue proper. Muscle tissue includes skeletal, cardiac and smooth muscle and has the ability to contract. Nervous tissue coordinates and controls body activities through electrical nerve impulses.