Kinesiology 2222A/B Lecture Notes - Lecture 5: Keratin, Melanin, Dermis
21 Sep 2016
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Prof: skin that we see on people is dead tissue. Skin has appendages like hair (colour change, hair growth), skin colour, tattoos. Pound of skin (skin aka. dermis): epidermis (epi- meaning above) skin we see, dermis middle, hypodermis basically just fat, it is the connective tissue that we don"t associate to the skin. Made up of keratinized squamous epithelial cells, stratified epithelial where many cells are stacked on top of each other. Keratinized means there is a granule in each of the cells called keratin. Keratinocytes: 90% of the cells in the epidermis, tough and take up/carry melanin granules. Produce melanin which is a small pigment for uv protection. Have small dots on the apical surface to protect nuclei beneath it from uv damage. Melanocytes: 8% of the cells, bottom layer, colour granules, Merkel cells: sensory cells, responsible for the sense of touch. Langerhans cells: 2% macrophage cells which are scavenger cells, they clean/eat cellular debris.
