Anatomy Chapter 5 Skin

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Anatomy Chapter 5 Skin
2010-10-02 00:07:55
anatomy skin

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  1. What are epidermal dendritic cells ?
    They ingest foreign substances and are key activators for our immune system
  2. What tactile (Merkel) cells?
    function as a sensory receptor for touch
  3. Where is the stratum basale layer located?
    the deepest epidermal layer
  4. Why is stratum basale also called stratum germinativum?
    the mitotic nuclei seen is this layer reflect rapid division of these cells
  5. What is the stratum spinosum (prickly layer) made of?
    weblike system of intermediate filaments mainly pre-keratin tension-resisting filaments
  6. Stratum Granulosm (granular layer)
    • consists of three to five cell layers
    • keratinazation begins (cells fill with the protein keratin) cells flatten nuclei and organelles degin
    • to disintergate accumulate two types of granules
    • keratohyaline granules- help to form keratin in the upper layers
    • lamellated granules- contain a water resistant glycolipid that is spewed into the extracellular space and a major factor slowing water loss across the membrane
  7. Stratum Lucidum ( Clear Layer)
    • thin translucent band just above the stratum granulosum
    • two to three rows of clear, flat,dead keratinocytes with indistinct boundaries
    • visible only in thick skin
  8. Stratum Corneum
    • outermost layer 20-30 cell layers thick
    • keratin and the thickened plasma membrane of cells in this stratum protects the skin against abrasion and penetration
    • protects the deep layers from the external hostile environment
    • shingle-like cell remnants are referred to cornified (dandruff)
  9. Dermis
    • second major skin layer, contains fibroblasts, macrophages, mast cells, and white blood cells
    • richly supplied with nerve fibers, blood vessels, and lymphatic vessels
  10. Papillary ( Dermis)
    • areolar connective tissue fine collagen and elastic fibers interlaced with blood vessel
    • its superior surface is thrown into peglike projections called dermal papillae that indent the overlying epidermis
  11. Recticular ( Dermis)
    • accounts for 80% of the thickness of the dermis, coarse irregularly arranged dense connective tissue(fibrous)
    • cutaneous plexus lies between this layer and the hypodermis
    • cleavage lines and flexure lines

    flexure lines are dermal folds that occur or near joints where the dermis is tightly secured (wrists, finger and toes, palms, and soles)
  12. Melanin
    • a polymer made of tyrosine amino acids
    • color range yellow to tan and reddish-brown to black
    • melanocytes are stimulated to greater activity by chemicals secreted by the surrounding
    • keratinocytes when we expose our skin to sunlight
  13. Carotene
    • yellow to orange pigment
    • accumulates in the stratum corneum and its fatty tissue of the hypodermis
    • found in the palms and soles
    • converted to vitamin A
  14. Sweat glands (sudoriferous)
    • distributed over the entire skin surface
    • eccrine glands- far more numerous and are particularly abundant on the palms, sole of the feet
    • coiled tubular gland, secretory pile lies in the dermis, and the duct opens to the skin surface

    • Appocrine sweat glands- 2000 found in the axillary and the anogenital area
    • release their product exocytosis lie deeper in the dermis and hypodermis
  15. Sebaceous (oil) glands
    • simple avelolar branched glands that are all over body except the palms and soles
    • secrete sebum- accumulate oil lipids until they burst holocrine glands
    • lubricates the hair prevent from being brittle