BACKGROUND: A tissue is a group of cells that have a similar shape and function. Different types of tissues can be found in different organs. In humans, there are four basic types of tissue: epithelial, connective, muscular, and nervous tissue.There may be various sub-tissues within each of the primary tissues. system is a group of organs each of which contributes its share to the function of the body as a whole. 1  Use the worksheet to go over the four tissues of the Human Body. 2  Make them take notes about each of the tissues and have them research where these tissues may be in the human body.