BLG 10A/B Lecture Notes - Lecture 5: Stratum Granulosum, Stratum Corneum, Stratum Basale
18 Mar 2014
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Document Summary
The skin and its derivatives (sweat and oil glands, hairs, and nails) make up a complex set of organs. In thick skin, the epidermis has 5 layers/strata; from deep to superficial: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum and stratum corneum. Deepest epidermal layer, attached to underlying dermis along wavy borderline. Several cell layers thick; contain web-like intermediate filaments of pre-keratin filaments, which span their cytosol to attach to desmosomes. Thin layer consists of 3-5 cell layers; keratinocyte appearance changes. Appears as a thin translucent band; 3-4 layers of clear, fat, dead keratinocytes. Gummy substance of keratohyaline granules clings to keratin filaments in the cells, causing them to aggregate in large, cable-like, parallel arrays. Broad zone 20 to 30 cell layers; of epidermal thickness. Keratin and thickened pm protect skin against abrasion and penetratin. Shingle-like ell remnants are cornifield or horney cells dandruff. Melanin, carotene and hemoglobin contribute to skin colour.
