BIOL 225, CH 6

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BIOL 225, CH 6
2011-03-23 13:27:22
Integumentary System

Ch. 6, the integumentary system
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  1. The 3 major regions of the skin (integument):
    • 1. epidermis (outermost superficial)
    • 2. dermis (middle)
    • 3. hypodermis (superficial fascia-deepest)
  2. the epidermis is composed of what types of cells?
    stem cells, keratinocytes, melanocytes, tactile (merkel) cells, and dedritic cells
  3. undifferentiated cells found only in the stratum basale that divided and give rise to keratinocytes
    stem cells
  4. cells that synthesize keratin and make up a great majority of the epidermal cells
  5. cells that appear only in the stratum basale; they synthesize the brown to black pigment melanin which shields the DNA from UV radiation
  6. cells that are associated with an underlying dermal nerve fiber
    tactile (merkel) cells
  7. cells found in the stratum spinosum and stratum granulosum (800 per sq mm). they are macrophages that originate in the bone marrow but migrate to the epidermis and epithelia of the oral cavity, esophagus and vagina. when invaders are detected they alert the immune system.
    dendritic (langerhans) cells
  8. list the layers of the epidermis from deep to superficial
    • 1. stratum basale
    • 2. stratum spinosum
    • 3. stratum granulosum
    • 4. stratum lucidum
    • 5. stratum corneum
  9. •Very thick stratum corneum
    •No hair
    •Deep/High derma ridges
    •No Sebaceous glands
    •Numerous eccrine glands
    thick skin
  10. •Lots of blood vessels
    •Nutrients for Epidermis
    •Sensory Receptors
    -the two layers are?
    dermis; the papillary and reticular layers
  11. where nerve endings called thermoreceptors regulate body temp by sending signals to the brain, which then sends them back to the dermal blood vessels. types?
    thermoregulation; vasoconstriction and vasodilation
  12. when cold, blood vessels narrow and reduce the blood flow close to the skin surface reducing heat loss
  13. when overheated, blood vessels widen increasing cutaneous blood flow which increases heat loss
  14. a thin zone of areolar tissue in and near the dermal papillae. this loosely organized tissue allows for mobility of leukocytes and other defenses agains organisms introduced through breaks in the epidermis
    papillary layer
  15. –80% of skin thickness
    –Dense irregular connective tissue
    –Collagen and Elastin fibers, Pacinian Corpuscles, Hair follicles, Sebaceous glands and Sweat glands
    reticular layer
  16. subcutaneous tissue that pads the body and binds the skin to the underlying tissues. drugs are injected into it because it is highly vascular making it able to absorb them quickly. adipose tissue serves as an energy reservoir and thermal insulator.
  17. the three pigments of skin color are
    melanin, carotene, and hemoglobin
  18. Made by Melanocytes
    Taken up by Keratinocytes
    –Variation in Color
    •Eumelanin - brown to black pigment
    •Pheomelanin - yellow to red
    –Variation in amount of melanin/cell
    –Variation in duration
    –Production stimulated by UV light
    –Freckles & pigmented moles
  19. a yellow to orange pigment acquired from diet, most obvious in palms and soles
  20. red pigment of blood; is enhanced when surface blood vessels are dilated
  21. leading cause of accidental death, treated by fluid replacement and infection control
  22. damages epidermis only, symptoms are local redness, swelling, and pain. heals in a few days and seldom leaves scars
    1st degree burn
  23. damages epidermis and upper dermis, symptoms are redness, swelling, pain, and blisters. takes 2wks-mths to heal and may leave scars
    2nd degree burn
  24. damages epidermis and dermis and destroys nerve endings causing no initial pain. burned area is gray-white, red, or black and skin often requires skin grafts
    3rd degree burn
  25. what are the three types of skin cancer?
    • 1. basal cell carcinoma
    • 2. squamous cell carcinoma
    • 3. melanoma
  26. skin cancer that is:
    •Least malignant, most common
    •Stratum basale cells proliferate, invade dermis & hypodermis
    •Slow growing, rarely metastasize
    •Surgical excision 99% successful
    basal cell carcinoma
  27. skin cancer that:
    •Arises from keratinocytes of stratum spinosum
    •Usually on scalp, ears, and lower lip
    •Grows rapidly, metastasizes if not removed
    •Good prognosis with radiation therapy or surgical removal
    squamous cell carcinoma
  28. •Cancer of melanocytes - the most dangerous
    –Highly metastatic
    –Resistant to chemotherapy
    Treat with wide surgical excision and immunotherapy