BSCI 201 Lecture 8: lecture 8- Integumentary
6 Oct 2016
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Document Summary
Cells of epidermis- mostly keratinized stratified squamous epithelium. Dendritic cells/ langerhans cells: star-shaped macrophages in deep epidermis. Keratinocytes: most abundant- everybody has the same amount of keratinocytes, produce fibrous keratin (protection, tightly connected by desmosomes, millions slough off everyday. Melanocytes: spider-shaped cells in deep epidermis, produce the pigment melanin transferred to melanosomes transferred to keratinocytes (where they protect nucleus from uv damage) Layers of epidermis- buy some good looking candy. Also known as stratum germinativum bc single layered cells constantly undergoing mitosis: one daughter cell goes from basal layer to surface and it dies as it moves, other daughter cell remains in stratum basale as stem cell. Keratinocytes are spikey (prickle cells: weblike pre-keratin protein attached to desmosomes (helps resist tension and pulling) 4~6 layers of cells: cells flatten, nuclei and organelles disintegrate, at upper layer, cells are beginning to die- too far from dermal capillaries to survive. Keratinization: keratohyaline granules- form keratin fibers in upper layers.
