The skin and its accessory structures (glands, nails, and hair) constitute the integumentary system. The skin is an organ because it conssits of several kinds of tissues that are structurally arranged to function together. It covers approximately 3000 sq. in, making it the largest organ. It is of variable thickness, averaging 1.5 mm. It is [...]

1. define “carcinoma”. 2. define “malignant”. 3. define “metastatic”. 4. briefly describe basal cell carcinoma. 5. briefly describe squamous cell carcinoma. 6. briefly describe malignant melanoma. 7. identify the ABCDs of examining skin cancer lesions. a. A – asymmetric shape. b. B – border that is irregular or diffuse. c. C – color that is [...]

Below are the three levels of burn severity, as well as some important information. 1st Degree Burn: rednes, pain and no tissue damage (sunburn). 2nd Degree Burn: blistering, pain and upper epidermal damage. 3rd Degree Burn: no pain (no remaining nerves), charred epidermis, exposed and damaged dermis; is life-threatening if over large body surface.

The epidermis is the superficial protective layer of the skin. It is derived from the ectoderm, and is composed of stratified squamous epithelium that varies in thickness from .007 to .12 mm. All but the deepest layers are composed of dead cells. Areas exposed to high friction have 5 layers; areas not exposed to high [...]

These are specialized structures at plasma membrane that link adjacent epithelium. Macromolecules are unable to pass through.

The presence of hair is a distinguishing feature of mammals. Men and women have the same density of hair, but testosterone makes the hair more apparent on men. The primary functions of hair are protection and attraction. Each hair consists of a diagonally positioned shaft, hair and bulb. The shaft is the visible, but dead, [...]

The dermis is thicker and deeper than the epidermis. Elastic and collageous fibers are arranged in definite patterns to produce lines of tension and provide skin tone. There are many more elastic fibers in the dermis of a young person than an old one. The extensive network of blood vessels in the dermis provides nourishment [...]

Keratinocytes produce keratin, which toughens and waterproofs the skin.