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11 Cards in this Set
- Front
- Back
Only organ is the skinI. Functions of system
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) Protection: a) Physical - stratified squamous epithelium keeps pathogens out.
b) Chemical - melanin blocks uv rays. c) cellular-white blood cells (macrophage) eat and destroy invading bacteria |
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2) Prevents water loss
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tough scaly epidermis, oily secretions prevent water loss.
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3) Thermoregulation:
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a) sweat secretions allow evaporative cooling
b) altered blood flow allows changes in skin temperature |
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4) Sensation
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all receptors in dermisa) Touch receptors - Meissner s corpuscles-touch
b) Pressure receptors - Pacinian corpuscles-pressure c) Pain receptors - bare/naked/free dendrites-pain/damage |
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5) Vitamin D
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(Calcitriol) productionVit D is important in promoting calcium absorption by intestine.
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II. Structure:Composed of three LAYERS
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Epidermis layer, Dermis layer, Hypodermis layer: the subcutaneous layer
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Epidermis layer:
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- The superficial layer - Made of a keratinized stratified squamous epithelium, avascular
1) Stratum Basale/Germinativum:the deepest layer is an active zone of cell division contains melanocytes that increase pigmentation (melanin) and therefore protection against UV radiation from sun 2) Stratum Corneum:the most superficial layer forming 75% of the epidermis.20 - 30 cell layers thick with all cells dead which is constantly shed, thereby removing attached pathogens. |
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Dermis layer:
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- Made of dense irregular connective tissue.- Vascular.
- Contains leucocytes (white blood cells) that digest pathogens - Contains glands, receptors, hair follicles, etc. |
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Hypodermis layer: the subcutaneous layer
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- Mostly adipose tissue
- For energy storage and thermal insulation. - Anchors the skin to the muscles. |
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A. Sweat/Sudoriferous Glands:
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They cover the entire body except the nipples and external genitalia.Abundant on the palms, soles, and forehead.Produce sweat that reduces body temperature.Also acts as an antibiotic, killling bacteria.
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Ceruminous: produce ear wax in the acoustic canal.catches debris entering ear.
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Sebaceous Glands:Found everywhere except the palms and soles.Secrete sebum (oil) into hair follicles to reduce loss of water. Also acts as an antibiotic, killling bacteri
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