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13 Cards in this Set
- Front
- Back
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What constitutes an Organ? |
Two or more kinds of tissues grouped together and performing specialized functions. |
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What are the functions of the Skin? (9) |
* Protective covering * Maintains homeostasis * Prevents water loss * Thermoregulation * Synthesizes chemical *Secretes * Excretes small amounts of waste * Sensation * Immune system cells |
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Describe the Epidermis. (3) |
* Keratinized stratified squamous epithelium * Four cells types * Four or five distinct layers |
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What are the four cell types found in the Epidermis? |
* Keratinocytes * Melanocytes * Dendritic cells * Tactile cells |
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Describe Keratinocytes. (3) |
* Most epidermal cells * Produce Keratin * Fibrous protein that gives the epidermis its protective properties |
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Describe Melanocytes. (2) |
* Spider shaped epithelial cells that synthesize melanin * Found in the deepest layer of the epidermis |
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Describe Dendritic cells. (4) |
* Star shaped * Arise from bone marrow and migrate to the epidermis * Also called Langerhans cells * Form a continuous network |
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Describe Tactile cells. (5) |
* Shaped like a spiky hemisphere * Present at the epidermal-dermal junction * Also called Merkel cells * Each is intimately associated with a disc-like sensory ending * Sensory receptor for touch |
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What are the four layers of the Epidermis, from the bottom up? |
* Stratum Basale * Stratum Spinosum * Stratum Granulosum * Stratum Corneum |
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Describe the Stratum Basale. (3) |
* One row of actively miotic stem cells * Some newly formed cells become part of the more superficial layers * Occasionally have melanocytes & dendritic cells |
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Describe the Stratum Spinosum. (2) |
* Several layers of Keratinocytes unified by desmosomes * Contain thick bundles of intermediate filaments made of pre-keratin |
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Describe the Stratum Granulosum. (3) |
* 5 layers of flattened cells * Organelles deteriorating * Cytoplasm full of lamellar granules (which release lipids) and keratohyaline granules |
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Describe the Stratum Coreum (4) |
* Top layer * 20-30 layers of dead cells * Flat membranous sacs filled with keratin * Glycolipids in ECM |
