Also known as adrenalin. (CS 2 & 5) ??? ??? ??? epithelial cells Cells that cover all surfaces of the body. (CS 3, 4, 6 & 7) ??? ??? ??? epithelial tissue A tissue that covers a surface or lines a space inside the body, forming a barrier or interface across which substances are absorbed or secreted, e.g. the skin, gut lining, and various glands. (CS 4 & 6) ??? ??? ??? equivalent dose A measure of