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Integumentary System

Skin Disorders

Some skin disorders result from overexposure to the ultraviolet (UV) rays in sunlight. At first, overexposure to sunlight results in injury known as sunburn. UV rays damage skin cells, blood vessels, and other dermal structures. Continual overexposure leads to leathery skin, wrinkles, and discoloration and can also lead to skin cancer. Anyone excessively exposed to UV rays runs a risk of skin cancer, regardless of the amount of pigmentation normally in the skin. Seventy-five percent of all skin cancers are basal cell carcinomas that arise in the epidermis and rarely spread (metastasize) to other parts of the body. Physicians can surgically remove basal cell cancers. Squamous cell carcinomas also occur in the epidermis, but these tend to metastasize. Malignant melanomas are life-threatening skin cancers that metastasize rapidly. There can be a 10-20 year delay between exposure to sunlight and the development of skin cancers.



Czarnecki, D. "10-Year Prospective Study Of Patients With Skin Cancer." Journal of Cutaneous Medicine and Surgery 6, no. 5 (2002): 427-429.

Fackelmann, Kathy A. "Skin Cancer's Return: How Big a Threat?" Science News (June 27, 1992).

Willis, Judith Levine. "Acne Agony." FDA Consumer (July-August 1992).


Skin Deep. Video and videodisc. Princeton, NJ: Films for the Humanities and Sciences, 1995.

Bernice Essenfeld


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—Polysaccharide that forms the exoskeleton of insects, crustaceans, and other invertebrates.


—The internal layer of skin lying below the epidermis. It contains the sweat and oil glands, hair follicles, and provides replacement cells for those that are shed from the outer layer.


—The thinner, outermost layer of the skin. Also the thin outermost covering in plants.


—Insoluble protein found in hair, nails, and skin.


—Brown-black pigment found in skin and hair.

Additional topics

Science EncyclopediaScience & Philosophy: Incomplete dominance to IntuitionismIntegumentary System - Plant Integumentary System, Invertebrate Integuments, Human Integumentary System, Skin Disorders - Vertebrate integumentary systems