Melanocyte, Melanosome, Melanin

  • Physiology
  1. Located in Basal Cell Layer of skin
  2. Melanosome organelles are produced by Melanocytes
    1. Melanosome transferred to Keratinocytes
  3. Melanin (brown pigment) produced within Melanosome
    1. Tyrosine converted to Melanin
    2. Melanin screens out sunlight ultraviolet rays
  4. Hyperpigmentation
    1. Increased Melanosomes
      1. Sun Exposure
      2. Hormonal control
        1. See Hyperpigmentation in Pregnancy
    2. Darker Skin Color in certain ethnic groups
      1. Same number of Melanosomes as lighter skin
      2. Darker skin results from larger Melanosomes
    3. Other factors affecting pigmentation
      1. Skin vascularity
      2. Presence of Carotene
      3. Thickness of Stratum Corneum