 |
Skin is the body’s largest organ. About six pounds of skin cover
eighteen square feet on an average adult.
The top layer of skin is called the epidermis. It protects the
underlying skin layers from the outside environment and contains
cells that make keratin, a substance that waterproofs and
strengthens the skin. The epidermis also has cells that contain
melanin, the dark pigment that gives skin its color. Other cells in
the epidermis allow us to feel the sensation of touch and provide
the body with immunity against foreign invaders like germs and
bacteria.
The very bottom layer of the skin is the hypodermis. It contains
the fat cells, or adipose tissue, that insulate the body and help
it conserve heat. The layer between the epidermis and the
hypodermis is the dermis. It contains the cells that give skin
strength, support, and flexibility. As a person ages, the cells in
the dermis lose their strength and flexibility, causing the skin to
lose its youthful appearance.
Located in the dermis are sensory receptors. They allow the body to
receive stimulation from the outside environment and experience
pressure, pain, and temperature. Small blood vessels provide the
skin with nutrients, and remove its waste products.
Sebaceous glands produce the oil in the skin, which keeps it from
drying out. The oil from the sebaceous glands also helps to soften
hair and kill bacteria that get in the skin’s pores. These oil
glands are all over the body, except on the palms of the hands and
the soles of the feet.
|
 |
