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Integumentary System. What is the integumentary system?. Skin Also called cutaneous membrane (combination of epithelial and connective tissue). Function of the Integumentary System. Protective covering Regulates body temperature Manufactures Vitamin D Sensory function
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What is the integumentary system? • Skin • Also called cutaneous membrane (combination of epithelial and connective tissue)
Function of the Integumentary System • Protective covering • Regulates body temperature • Manufactures Vitamin D • Sensory function • Temporary storage of fat, glucose, water and salts • Screens out harmful UV radiation • Absorbs certain drugs
Structure of Skin • 2 distinct tissue layers • Epidermis = stratified squamous epithelium • Dermis = connective tissue, epithelial tissue, smooth muscle, nervous tissue, and blood • Under these layers is subcutaneous layer (NOT SKIN) • Loose connective tissue & adipose tissue that binds skin to other organs
Structure of skin Which is the thicker layer?
Melanocytes • Cells that produce melanin • Melanin provides skin pigment • Shade of skin is also dependent on environment
What determines skin color? • Distribution and size of pigment granules • Sunlight, UV light, x rays • Blood in dermal vessels • bright red blood pink skin • Dark red blood bluish (cyanosis) • Dilated blood vessels red skin
Layer between dermis and epidermis • Ridges lead to finger prints • Patterns of ridges determined by genes and fetal movement • Would identical twins have the same fingerprints?
Dermis • ~1.0-2.0 mm thick • Composed of: • Dense connective tissue (collagen & elastic fibers) • Muscle fibers • Nerve cells (usually connected to sensory receptor) • Blood vessels • Hair follicles • Sebaceous glands • Sweat glands
In the dermis there are many accessory organs: • Hair • Nail • Sebaceous glands • Sweat glands
Hair follicle = tube-like depression • Hair root = portion of hair in skin • Hair papilla = cells responsible for hair growth • Hair shaft = hair that extends from skin (composed of keratinized cells) • Arrectorpili = muscle attached to follicle
Nail plate = on surface of skin • Nail bed = skin under nail • Lunula= white, half-moon shaped area at bottom of nail plate • Actively dividing • Why would nails mirror health?
Bluish nail beds = circulation problems • White nail bed/oval depressions = anemia • Pigmented spot = injury or melanoma • Horizontal furrows = period of serious illness or malnutrition
Sebaceous glands • Found near hair follicles • Specialized epithelial cells • Produce sebum (fatty material & cellular debris) • Keeps skin soft, pliable, waterproof • What does excess sebum cause?
Sudoriferous/Sweat Glands • Found in deep dermis • Respond to body temperature