The integumentary system contains the largest organ in the human body, the skin. Hair and nails, are also part of integumentary system as the extension of the skin. The skin, however, is the most important. All these structures together, provide protection to the inner tissues of the body. Protection is the most important function of the integumentary system. The skin is a waterproof layer that holds in all the moisture within our body and helps regulates body temperature. It works as a physical barrier against microorganisms entering the body that causing integumentary system diseases.
However, skin is just like a simple covering of our body but it is the most important sensory organ that helps us relays signal to the brain about our surroundings. It responds to every single touch, pressure, pain and even the changes in temperature. The skin consist of two layer tissues, the epidermis on the surface and the dermis underneath. These tissues in the skin of human body are made up of four, the epithelial tissue, muscle tissue, nervous tissue and connective tissue. Epidermis is epithelial tissue, it is the thin outer layer of the skin.
Most of them are dead cells and these contains protein called keratin, it waterproofs and protects tissues underneath. In the lower layer, it produces a pigment called melanin which protects the skin cells from damaging effects of ultraviolet from the sun. The dermis, is connective tissue and the thicker portion of the skin and consist of sweat glands, hair follicles, nerves and blood vessels that maintain the health of live cells. Beneath the dermis is the adipose tissue, the subcutaneous layer, a fat storage that insulate the body from cold.