PHAR 303 Lecture Notes - Lecture 18: Stratum Corneum, Keratinocyte, Sebaceous Gland
15 Feb 2018
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Document Summary
Epidermis: the uppermost layer: there is a turnover of cells in the epidermis all the time. In an inch, in a square section of skin: there are millions of cells, blood vessels, nerves, sweat glands, sebaceous glands etc. At the same time, it is also shedding millions of cells. Keratinocytes: formed in the start in the base, and work their way up. At the stratum corneum: dead keratinocytes are packed on the top. Keratinocytes have a lifespan of 4 weeks until they are shed off completely from the surface of the skin. The dead ones are held together by lipids in between them. Melanocytes: make the melanin in little granules and insert these little granules to the keratinocytes cells get the pigmented colors. Langerhans cells: from bone marrow, part of immunological cell type. Brings nutrients that can fuse in the epidermis: contain blood vessels and lots of fibroblasts, and make collagen, elastin these make the main structure of the skin.
