| Term | Definition |
|---|
| organ system of epidermis | integument |
| characteristics of epidermis | avascular, five layers |
| layers of epidermis | stratum basal, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum |
| stratum basal (germinivatum) | one row of cells, closest to blood vessels, mitotic, creates other layers, cuboidal cells |
| stratum spinosum | 8-10 rows, white blood cells travel through desmosomes, weakly mitotic |
| "spino" | horny |
| stratum granulosum | granules of kertohyaline, 3-5 rows, stains dark, cells die, nuclei begin to disentigrate |
| stratum lucidum | only present in thick skin, 3-5 rows, dead, no nuclei, enzymes convert kertohyalin to eleiden |
| stratum corneum | kerotinized, tough, resistant, waterproof, sheds particles |
| cells of epidermis | keratinocyte (95%), melanocytes, langerhan's cells, merkel cells |
| melanocytes | make melonin, puncture keratinocytes and pump them with melanine (pigment), activity levels vary |
| more active melanocytes | darker skin, freckles |
| less active melanocytes | light skin |
| tyrosine | inability to create this enzyme results in albinism |
| effect of uv light on melanocytes | increases activity level |
| pros of uv light | vitamin D |
| cons of uv light | high energy radiation damages DNA leading to sickness, mutations, cancer |
| color range of melanin | yellowish to black |
| factors in skin color | melanin, carotene (from plant foods), blood (vasocontriction, vasodilation) |
| langerhan's cells | white blood cells that crawl through desmosomes, alert immune system |
| nickname for langerhan's cells | "sentinel cells" |
| merkel cells | assist nervous system in light touch |
Combine with other sets
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