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31 Cards in this Set
- Front
- Back
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Skin: Functions |
1.Protection - Cushions organs and protects from bumps, chemicals, water loss, UV radiation 2.Regulation of Body Temperature 3.Excretion - Urea, salts, and water lost through sweat 4.Sensory Reception - Receptors keep us aware of conditions at the body surface |
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Epidermis: 4 main cell types Keratinocytes |
Location: Stratum Spinosum
Produce keratin: fibrous protein that gives epidermis its protective properties -also make antibodies, and enzymes
Most abundant cell type Dead at skin surface |
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Epidermis: 4 main cell types Melanocytes |
Location: Basal Layer Manufacture and secrete pigment Secrete signaling molecules in response to UV radiation -Modulate immune response in skin (tanning) -Influence inflammatory response |
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Epidermis: 4 main cell types Tactile Epithelial Cells |
Location: Basal Layer Attached to sensory nerve endings |
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Epidermis: 4 main cell types Dendritic Cells |
Location: Stratum Spinosum Part of immune system; macrophage-like -Monitor out body surface via receptor-mediated endocytosis (Antigens) -Cells travel from skin to nearby lymph node |
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Layers of Epidermis (Lowest to highest) |
Basale Spinosum Granulosum Lucidum Corneum |
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Layers of the Epidermis: Stratum Basale |
Deepest layer of epidermis Attached to underlying Dermis Cells actively Divide Contains: Merkel Cells - associated with sensory nerve ending Melanocytes - secrete pigment melanin |
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Layers of the Epidermis: Stratum Spinosum |
"Spiny" appearance caused by: Artifacts of histological preparation Contains thick bundles of intermediate filaments -Resists tension -protein prekeratin Contain star-shaped dendritic cells -Macrophage -Function in immune system |
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Layers of the Epidermis: Stratum Granulosum |
Consists of Keratinocytes and tonofilaments Tonofilaments contain: -Keratohyaline granules - help form keratin -Lamellated granules - contain a waterproofing glycolipid |
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Layers of the Epidermis: Stratum Lucidum |
Occurs only in thick skin Location of thick skin - palms and soles
composed of a few rows of flat, dead keratinoctyes |
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Layers of the Epidermis: Stratum Corneum |
Thick layer of dead keratinocytes and thickened plasma membranes
Protects skin against abrasion and penetration |
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Dermis |
Second major layer of skin Strong, flexible connective tissue Richly supplied with blood vessels and nerves |
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Dermis: 2 layers |
Papilary layer - dermal papilae Reticular layer - Deeper layer, 80% thickness of dermis |
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Hypodermis |
Deep to the skin, superficial fascia Contains areolar and adipose connective tissue Anchors skin to the underlying structures Helps insulate body |
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Skin Color: 3 pigments |
Melanin: Most important, made from tyrosine Little found in caucasian skin
Carotene: Yellowish pigment from carrots and tomatoes
Hemoglobin: Allows crimson color of blood to show through |
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Nails |
Made of hard keratin Parts: Free edge Body Root Nail Folds Eponychium - cuticle |
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Appendages of the skin: Hair |
Flexible strand of dead, keratinized cells Hard keratin - tough and durable |
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Chief parts of hair |
Root - imbedded in the skin Shaft - projects above the skin's surface |
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Hair: Three concentric layers of keratinized cells |
Medulla - central core Cortex - surrounds medulla Cuticle - outermost layer |
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Hair Follicles |
Extend from Epidermis into Dermis |
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Hair Bulb |
Deep, expanded end of the hair follicle |
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Root Plexus |
Knot of sensory nerves around hair bulb |
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Arrector pili muscle |
Bundle of smooth muscle Hair stands erect when arrector pili contracts |
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Types of Growth of Hair: Vellus Hairs |
Body hairs of women and children |
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Types of Growth of Hair: Terminal HAir |
Hair of scalp Axilary and pubic area (at puberty) |
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Sebaceous Glands |
Occur over entire body (Minus palms/soles) Secrete Sebum - oily substance -Simple alveolar glands -Holocrine secretion: Entire cell breaks up to form secretion -Most associated with hair follicle |
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Functions of Sebum |
Collects dirt Softens and lubricates hair and skin |
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Sebaceous Glands: Sweat Glands |
Widely distributed throughout body |
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Sweat |
Blood Filtrate 99% water with some salts Contains traces of metabolic wastes -2% Eurea |
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2 Types of Sweat Glands: Eccrine Gland |
Most numerous These produce sweat |
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2 Types of Sweat Glands: Apocrine Gland |
Confined to axillary, anal, and genital areas Produce special sweat -musky odor to attract a mate
Ceruminous glands and mammary glands -Modified apocrine glands |
