๐ ็ธฝ็ฎ้ ๏ฝ ๐ ่ฑๆๅๆ๏ผๆฌ็ฏ๏ผ ๏ฝ ๐ ๅฎๆด็ฟป่ญฏ ๏ฝ โญ ็ฒพ่ฏ็ญ่จ
Introduction
Jean L. Bolognia and Seth J. Orlow Melanocyte Biology
Key features
ยThe major determinant of normal skin color is the activity of melanocytes, i.e. the quantity and quality of pigment production, not the density of melanocytes
ยMelanocytes contain a unique intracytoplasmic organelle, the melanosome, which is the site of melanin synthesis and deposition
ยCompared with lightly pigmented skin, darkly pigmented skin has melanosomes that contain more melanin and are larger; once transferred to keratinocytes, the melanosomes are singly dispersed and degraded more slowly
ยTyrosinase is the key enzyme in the melanin biosynthetic pathway
ยTwo major forms of melanin are produced in melanocytes: brownโ black eumelanin and yellowโred pheomelanin
ยThe production of eumelanin versus pheomelanin is influenced by the binding of melanocyte stimulating hormone to the melanocortin 1 receptor