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Integumentary System

Integumentary System. Skin and accessory structures (hair, nails) Integument means covering. Functions. Protection Against UV light, entry of pathogens, abrasions, water loss Sensation Sensory receptors detect heat, cold, touch, pressure, pain Temperature regulation

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Integumentary System

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  1. Integumentary System Skin and accessory structures (hair, nails) Integument means covering

  2. Functions • Protection • Against UV light, entry of pathogens, abrasions, water loss • Sensation • Sensory receptors detect heat, cold, touch, pressure, pain • Temperature regulation • By controlling blood flow and sweat glands • Vitamin D production • In UV light, skin produces a molecule that can be transformed into Vitamin D

  3. Vitamin D • Necessary for normal absorption of calcium from intestine • Rickets in children is a disease from reduced mineralization of bone matrix

  4. The skin consists of 2 layers 1. Epidermis • Outer layer • Stratified squamous • Contains no blood vessels • Has four types of cells • Most cells are Keratinocytes • Produce keratin • Melanocytes • Skin color, produced from melanin • Langerhans’ cells • Part of the immune system • Merkel’s cells • Detect light and pressure

  5. Epidermis • Cells are produced by mitosis in the deepest layer • New cells push older, dead cells to surface to slough off or desquamate • Keratinization is the process of moving older cells to surface because they fill with keratin. • These cells will resist abrasion and form a permeability barrier

  6. 5 layers of epidermal cells • Strata are regions of the epidermis • Stratum Corneum • Stratum Lucidum • Stratum Granulosum • Stratum Spinosum • Stratum Basale

  7. An easy trick to remember these 5 epidermal layers in order from the most superficial to the deepest: "Can Little Girls Speak British" • Can Corneum • Little Lucidum • GiRl GRanulosum • Speak SPinosum • British Basale

  8. Stratum Corneum • 25 + layers of dead skin • Cornified cells (dead cells with a hard protein envelope) • Hard keratin (nails, hair) • Soft keratin (skin)

  9. Stratum Lucidum • Thin, clear region • Dead cells • Only found in thick skin (palms, soles of feet, fingertips)

  10. Stratum granulosum • 2-5 layers of diamond shaped cells • Most cells are dead • Keratohyalin granules • protein envelope that forms below plasma membrane

  11. Stratum spinosum • 8-10 layers of flatten cells • Some mitosis occurs • Lamellar bodies form (organelle containing lipids) • Abundant Langerhans cells

  12. Stratum basale • Deepest layer • Single layer of cuboidal/columnar cells • Mitosis occurs every 19 days • One daughter cell pushes to surface to become keratinized (40-56 days) • Contains merkel cells and melanocytes

  13. Thick and Thin Skin • Thick • All 5 strata • Areas subject to pressure and friction (soles of feet, palms of hands, fingertips) • Thin • 4 layers • Hair present • Callus is increased layer of strata corneum

  14. Hypodermis • Subcutaneous tissue • Not a part of skin • Foundation for dermis • Supplies blood vessels and nerves • Adipose abundant • Half of body fat

  15. Dermis • Deeper layer • Exchanges gases, nutrients, wastes from epidermis • Comprised of 2 layers • Responsible for strength and flexibility

  16. 2 layers of dermis • 1. Reticular region • Collagen and elastin fibers • Dense, irregular connective • Cleavage/tension lines • Stretch marks (overstretched, ruptured dermis) • 2. Papillary region • Papillae projections • Loose connective • Makes your fingerprints

  17. Skin color • Melanosomes (vesicle for carrying melanin) are produced by Golgi apparatus of the melanocytes • Melanin is a term used to describe a group of pigments responsible for color of hair, skin, eyes. (UV protection) • Melanosomes move into cell processes of the melanocyte • Epithelial cells phagocytize melanosomes • Production due to genes, hormones, sun exposure

  18. Skin color • Freckles = large amounts of melanin • Albinism = inability to produce melanin • Tanning= UV light darkens melanin and stimulates production • Carotene = yellow pigment in carrot/ corn that accumulates in stratum corneum and tints skin yellow • Cyanosis = bluish color from shock due to decrease in blood oxygen

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