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The Integumentary System. Chapter 20B. Functions of the Skin. Protection Sensation Temperature regulation Excretion Vitamin D manufacture Absorption. Layers of the Skin. Epidermis Dermis Subcutaneous layer. Epider mis. Outermost layer of skin, made of epithelial tissue
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The Integumentary System Chapter 20B
Functions of the Skin • Protection • Sensation • Temperature regulation • Excretion • Vitamin D manufacture • Absorption
Layers of the Skin • Epidermis • Dermis • Subcutaneous layer
Epidermis • Outermost layer of skin, made of epithelial tissue • stratum basale • keratin • stratum corneum
Epidermis • Disorders • blisters • calluses and corns • psoriasis
Dermis • Inner, thicker layer of skin • Connective tissues with blood vessels, nerve endings, sweat glands, hair follicles, and oil glands
Subcutaneous Layer • Not actually part of the skin • Attaches dermis to muscles • Made of connective tissues, including fat deposits
Burns • First-degree burns • Second-degree burns • Third-degree burns
Hair • The hair follicle is located in dermis; it contains the hair root. • The shaft of hair above the skin is made of dead, protein-filled cells.
Hair • Hair loss • Goose bumps
Nails • The visible portion is composed of dead cells filled with protein.
Exocrine Glands • Release secretions through ducts • Two types • sebaceous glands • sweat glands
Sebaceous Glands • Produce oil (sebum) that keeps the hair and skin soft • Acne
Sweat Glands • 150-300 sweat glands per square centimeter of skin • Produce perspiration • 99% water plus 1% salts, sugars, amino acids, and urea
Sweat Glands • 150-300 sweat glands per square centimeter of skin • Produce perspiration • elimination of waste • temperature control
Normally, the body excretes about a half-pint of water per day.
During strenuous exercise on a hot day, the body can lose up to 2 gallons of water.
Skin Color • Melanocytes produce melanin. • UV radiation stimulates the production of melanin.
Skin Color • Excessive sunbathing causes skin to age prematurely and may cause mutations that lead to skin cancer.
Diseases and Disorders • Ringworm • Warts