The sweat glands which consists of a coiled tubular gland opening into the epidermis, it excretes water and salta as sweat, sebaceous gland which produces an oily substance called sebum. This helps to lubricate the hair and makes it waterproof, while the erector muscle controls the erection of the hairs on the skin surface by its contraction and relaxation. Underneath the skin is a layer of fat subcutaneous fatty tissue. This fat layer varies in thickness, depending on the part of the body.