There are four major types of body tissue, and most parts of the body, including most organs, contain all four. For example, the heart pumps blood (connective tissue) through rhythmic contractions (influenced by the nervous system) of the myocardium (muscle tissue), and a sheet of cells called the endocardium (epithelial tissue) lines the heart chambers. Even very small regions of the body contain multiple types of body tissue. If some unlucky person steps on a tiny thumbtack (ouch!) and a little droplet of blood forms, how many types of tissue would likely be involved in the injury?