Term
| what are the main regions of the skin? |
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Definition
| Epidermis – outermost superficial region Dermis – middle region Hypodermis (superficial fascia) – deepest region |
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Term
What four cell types are in the epidermis?
(kmlm) |
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Definition
| Keratinocytes, Melanocytes, Langerhans Cells, and Merkel Cells |
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Term
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Definition
| produce the fibrous protein keratin |
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Term
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Definition
| produce the brown pigment melanin |
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Term
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Definition
| epidermal macrophages that help activate the immune system |
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Term
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Definition
| function as touch receptors in association with sensory nerve endings |
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Term
| what are layers in the epidermis? |
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Definition
| Stratum Basale, Stratum Spinosum, Stratum Granulosum, Stratum Lucidum, and Stratum Corneum |
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Term
| Layers of the Epidermis: Stratum Basale (Basal Layer) |
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Definition
Deepest epidermal layer firmly attached to the dermis
Consists of a single row of the youngest keratinocytes
Cells undergo rapid division, hence its alternate name, stratum germinativum |
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Term
| Layers of the Epidermis: Stratum Spinosum (Prickly Layer) |
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Definition
Cells contain a weblike system of intermediate filaments attached to desmosomes
Melanin granules and Langerhans’ cells are abundant in this layer |
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Term
| Layers of the Epidermis: Stratum Granulosum (Granular Layer) |
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Definition
Thin; three to five cell layers in which drastic changes in keratinocyte appearance occurs
Keratohyaline and lamellated granules accumulate in the cells of this layer |
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Term
| Layers of the Epidermis: Stratum Lucidum (Clear Layer) |
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Definition
Thin, transparent band superficial to the stratum granulosum
Consists of a few rows of flat, dead keratinocytes
Present only in thick skin |
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Term
| Layers of the Epidermis: Stratum Corneum (Horny Layer) |
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Definition
Outermost layer of keratinized cells
Accounts for three quarters of the epidermal thickness
Functions include:
Waterproofing
Protection from abrasion and penetration
Rendering the body relatively insensitive to biological, chemical, and physical assaults |
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Term
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Definition
Second major skin region containing strong, flexible connective tissue
Cell types include fibroblasts, macrophages, and occasionally mast cells and white blood cells
Composed of two layers – papillary and reticular |
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Term
| what are the layers of the Dermis? |
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Definition
| pillary Layer, Reticular Layer, and Hypodermis |
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Term
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Definition
Areolar connective tissue with collagen and elastic fibers
Its superior surface contains peglike projections called dermal papillae
Dermal papillae contain capillary loops, Meissner’s corpuscles, and free nerve endings |
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Term
| Reticular layer (thickest layer of the skin) |
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Definition
Accounts for approximately 80% of the thickness of the skin
Collagen fibers in this layer add strength and resiliency to the skin
Elastin fibers provide stretch-recoil properties |
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Term
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Definition
Subcutaneous layer deep to the skin
Composed of adipose and areolar connective tissue |
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Term
| what the three pigments of Skin Color? |
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Definition
Melanin – yellow to reddish-brown to black pigment, responsible for dark skin colors
Freckles and pigmented moles – result from local accumulations of melanin
Carotene – yellow to orange pigment, most obvious in the palms and soles of the feet
Hemoglobin – reddish pigment responsible for the pinkish hue of the skin |
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Term
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Definition
| found in palms, soles of the feet, and forehead |
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Term
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Definition
| found in axillary and anogenital areas |
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Term
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Definition
| modified apocrine glands in external ear canal that secrete cerumen |
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Term
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Definition
| specialized sweat glands that secrete milk |
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