Chapter 14 Section 4: Skin Key concepts: What are the functions and the structures of skin? What habits can help keep your skin healthy? Key terms: epidermis, melanin dermis, pore, follicle, cancer

The body’s tough covering Your skin covers and protects your body from injury, infection, and water loss. The skin also helps regulate body temperature, eliminate wastes, gather information and produce vitamin D.

Skin functions Protects your body – keeps stuff out and in Maintains temp Eliminates wastes – perspiration contains dissolved waste materials Gathers information – pressure, pain, temp Vitamin D producer – takes sunlight and makes vitamin D

Epidermis The skin is organized into two main layers, the epidermis and the dermis. Epidermis is the outer layer of the skin. It is usually thinner than the dermis.

Epidermis structure Each epidermal cell begins deep in the epidermis, where cells divide to form new cells. As they mature, cells move upward. After about two weeks, cells die and become part of the skin surface layer. Meaning you’re covered with dead stuff. You are the walking dead.

You

Epidermis function The protection provided by your skin is mostly due to the dead cells. The shedding of them also carries away bacteria. Melanin – produced deep in the epidermis – a pigment that gives skin its color

Dermis Dermis – inner layer of the skin. Below the epidermis. Contains nerves and blood vessels, sweat glands, hairs, and oil glands. Pores – openings in the skin Follicles – structures that produce strands of hair within the dermis

Caring for your skin Three simple habits: eat healthy, keep your skin clean and dry, limit your exposure to the sun Cancer – disease in which some cells divide uncontrollably