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Integumentary System. Chapter 45. 4. Integumentary System . Hair Skin Nails. Functions. Covers your body Retains body fluids Protects against diseases Protects from injuries Eliminates waste products Regulates body temperature Produces Vitamin D. Skin. Human body’s largest organ
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Integumentary System Chapter 45. 4
Integumentary System • Hair • Skin • Nails
Functions • Covers your body • Retains body fluids • Protects against diseases • Protects from injuries • Eliminates waste products • Regulates body temperature • Produces Vitamin D
Skin • Human body’s largest organ • Skin is capable of repairing itself through a lot of wear and tear throughout a lifetime • Made up of layers • Epidermis • Dermis • Subcutaneous
Epidermis • Outer layer of the skin • Composed of many sheets of flattened, scaly epithelial cells • TOP layer (corneal)of epidermis is mostly DEAD cells • UNDERNEATH the top layer (basal) are living cells that are rapidly dividing
Epidermis cont’d • Cells of the epidermis contain KERATIN • Protein that gives the skin its rough, leathery texture AND waterproof quality • Cells also have MELANIN • Brown pigment that gives skin its color • Melanocytes are the melanin-producing cells • Absorbs harmful UV radiation • Darker skin is due to more melanin being produced • Heredity and “tanning” • Light skinned people need to be careful with UV radiation • Can cause mutations in DNA, which lead to SKIN CANCER
Dermis • Inner, thicker layer of the skin • Composed of living cells and specialized structures • Sensory neurons • Blood vessels • Hair follicles • Glands • Nail
Sensory Neurons • Allow you to sense conditions and signals from your environment • Temperature • Pressure • Pain
Blood Vessels • Allow blood to flow to your dermis, providing nourishment to your living cells
Hair Follicles • Average adult has 5 million hairs on their body • Protects and insulates the body • Hair follicle is the cavity deep in the dermis where the hair grows out from • Tiny muscles are attached to your hair follicles • Goosebumps • Hair is actually composed of dead, keratin-filled cells that overlap each other like shingles on a roof • Hair color is due to melanin • Heredity
Glands • Exocrine Glands-glands that release secretions through ducts • 2 Main exocrine glands of the skin are OIL and SWEAT glands
Oil Glands • Oil glands • Prevent hair from drying out • Produce SEBUM-fatty substance • Coats the surface to prevent water loss • Softens skin and hair • Can be toxic to some bacteria • Production controlled by hormones • Adolescence and increased hormones result in higher activity of oil glands • Dead skin, bacteria and sebum cause ACNE
Sweat Glands • Releases excess water, salts, and urea • Helps regulate body temperature • Sweat is produced when body becomes hot • As sweat evaporates, the body cools
Fat and Pores • Fat is used to insulate body • Pores allow fluids to leave the body • Sweat, Oil • Oil or sweating clogging a pore can cause blackheads or pimples
Nails • Protect the end of fingers and toes • Composed mainly of keratin • Nails grow about 1mm per week • Growth begins at nail root • Nails rest on a nail bed which is composed of blood vessels, giving your nails their pink tint
Muscle and IntegumentaryVocab Quiz Tomorrow (Friday)!!!Chapter 45 Quiz Monday!!!