1. STRUCTURE AND FUNCTION

2.  Called three things:  1. Membrane—  because it covers the body  2. Organ—  because it contains several kinds of tissues  3. System—  because it contains organs that work together to perform specific functions

3.  Protection: Chemical, Physical, Biological  Body Temperature Regulation  Storage  Absorption  Excretion  Production or Metabolic Functions

4.  Outer layer/no blood vessels  95% of the cells are keratinocytes—keratin  Five different sub-layers  New skin cells-basal layer  Change from square to flat as move to the surface  Very tough; withstand scuffs and scrapes  Melanocytes and Langerhans cells  25-45 days  Function-continuous supply of new skin cells, resists friction, waterproof, and prevents water loss

5.  Stratum corneum (Horny layer) 15-25 layers of dead, flat, squamous, epithelial cells. Thicker over soles and palms  Stratum lucidum (clear layer) only located in the thicker areas  Stratum granulosum (Granular layer) waterproofing with keratin and lipids  Stratum spinosum (Prickly layer) usually the thickest layer, Langerhans cells—part of the immune response  Stratum basale (Basal cell layer) stem cells, keratinocytes, Merkel cells, and melanocytes

7.  Thicker than the epidermis  Provides epidermis with nutrients  Strong and flexible  Fibroblast cells—collagen and elastin  “body stocking”  Two layers: Papillary and Reticular  Hair follicles, sebaceous glands, blood vessels, and sense receptors

8.  Papillary  Phagocytes  Friction Ridges and fingerprints  Reticular  80% of the thickness of the dermis  Tension or cleavage lines  Flexure lines

9. http://www.google.com/imgres?q=friction+ridges+and+fingerprints&hl=en&biw=1280&bih=709&gbv=2&tbm=isch&tbnid=ffXiT SkxjG475M:&imgrefurl=http://jyotishmanrocks.blogspot.com/2011/05/invention-of- fingerprint.html&docid=PuqbsKJhPHg6QM&imgurl=http://daphnecaruanagalizia.com/wp- content/uploads/2010/06/fingerprint- 207x300.jpg&w=207&h=300&ei=AXrVTq2GIcSqgweGodi6AQ&zoom=1&iact=hc&vpx=447&vpy=139&dur=1390&hovh=240&hovw= 165&tx=120&ty=139&sig=108715678895446932678&page=1&tbnh=159&tbnw=110&start=0&ndsp=17&ved=1t:429,r:1,s:0 http://www.google.com/imgres?q=friction+ridges+and+fingerprints&hl=en&biw=1280&bih=709&gbv=2&tbm=isch&tbn id=v82nYzyzRpRjiM:&imgrefurl=http://quizlet.com/2728226/chapter-5-the-integumentary-system-flash- cards/&docid=QLSAz2WRh1AjuM&imgurl=http://i.quizlet.com/i/IAGlRO2vQXC5AKWB8U6_Hg_m.jpg&w=238&h=240&e i=AXrVTq2GIcSqgweGodi6AQ&zoom=1&iact=hc&vpx=913&vpy=314&dur=121&hovh=192&hovw=190&tx=92&ty=133&sig =108715678895446932678&page=1&tbnh=160&tbnw=112&start=0&ndsp=17&ved=1t:429,r:9,s:0

10. http://www.google.com/imgres?q=tension+lines+dermis&hl=en&biw=1280&bih=709&gbv=2&tbm=isch& tbnid=mbiY7-q7wRcr-M:&imgrefurl=http://teleanatomy.com/introductiontoanatomy- Skin.html&docid=5lxpGgsXiqcP9M&imgurl=http://teleanatomy.com/General%252520Anatomy/Introduct ion%252520to%252520Anatomy%2525203rd%252520Edition/Skin_files/image020.jpg&w=576&h=668&ei=q 3fVTuXTD4PDgQe89smYAQ&zoom=1&iact=hc&vpx=264&vpy=142&dur=49085&hovh=242&hovw=208&tx=5 3&ty=257&sig=108715678895446932678&page=1&tbnh=168&tbnw=145&start=0&ndsp=23&ved=1t:429,r: 1,s:0

11.  Not considered a skin layer  Subcutaneous tissue  Fat, blood vessels, and sensory receptors  Cushions and insulates

12.  MELANOCYTES  Everyone has the same #  Difference comes from the kind and amount of melanin made and retained  Protection from the sun  Freckles and moles  CAROTENE  Yellow to orange pigment, converted to Vitamin A  Asian  Palms, heels, and soles of feet  HEMOGLOBIN  Rosy complexion in fair skin

13.  Cyanosis  Poor oxygenation  Albino  Absence of color pigment  Erythema  Redness  Pallor, blanching  Loss of color  Jaundice  Yellow cast  Bronzing  Copper color  Hematomas  Black and blue marks/bruising

14.  Sweat Glands or sudoriferous glands  Up to 3 million per person  Two types: eccrine and apocrine  Eccrine—99% water  Primary purpose is to prevent overheating  Heat induced sweating begins on the forehead  Emotionally induced begins on the palms, soles, and axillae  Sebaceous Glands  Oil glands  Everywhere except palms and soles  Sebum  Blemishes

15.  Hair Follicles and Hair  Millions cover our bodies except…..  Protection  Pigment/Color—melanocytes  Red hair—pigment containing iron  Gray or white hair—decreased melanin  Arrector pili—”raiser of hair” muscle and secretes sebum out of the hair follicle  Normal hair loss  Fastest hair growth  Nutrition and hormones  Hirsutism  Alopecia  Baldness  Hair thinning

16.  Our “hooves” or “claws”  Protect fingers and toes  Useful as “tools”  Dead keratinized epidermal epithelial cells  Pink from rich bed of capillaries in the underlying dermis  Nail matrix  Changes in nail appearance:  Yellow-tinged  Thickened  Outward, concavity (spoon nail)  Horizontal lines (Beau’s lines)