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22 Cards in this Set
- Front
- Back
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Skin is the largest organ system. It covers 20 sq feet on an average adult.
- What are the two main layers and third one? |
- Epidermis
- Dermis - Subcutaneous (adipose tissue) |
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* Epidermis layer:
thin but tough - makes a rugged protective barrier. - What are the many stratified layers? |
- Stratum germinativum (inner/basal layer)
- Stratum corneum (outer horny cell layer) |
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* Stratum germinativum
(inner epidermis layer) - forms new skin cells - Major ingredient: tough, fibrous protein keratin - Melanocytes produce pigment melanin --> gives brown tones to skin and hair - Compare/contrast melanocytes in people? |
- People all have the same number of melanocytes --> but the amount of melanin produced varies --> genetic, hormonal, environmental influences
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* Stratum corneum
(outer epidermis layer) - Consists of? |
- dead keratinized cells (interwoven and closely packed)
- consistantly being shed (desquamated) - replaced with new cells from below, completely every 4 weeks |
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Epidermis is ___________, and nourished by blood vessels in the dermis blow.
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- Avascular
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Skin color is derived from what three sources:
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(1) mainly from the brown pigmetn melanin
(2) yellow-orange tones of the pigment carotene (3) the red-purple tones underlying vascular bed |
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Skin color is affected by three things:
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(1) relative proportion of shades (brown, red, yellow)
(2) thickness of skin (3) presence of edema |
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* Dermis layer:
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- The inner layer composed of connective tissue or collagen
- Tough, fibrous protein --> enables skin to resist tearing - Resilient elastic tissue --> allows skin to stretch with body movement |
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What four structures lie within the dermis?
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- nerves
- sensory receptors - blood vessels - lymphatics |
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What three appendages from the epidermis are also embedded in the dermis?
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- hair follicles
- sebaceous glands - sweat glands |
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* Subcutaneous layer:
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- Adipose tissue, made up of lobules of fat cells
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Subcutaneous layer stores fat for:
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- energy
- insulation for temperature control - aids in protection by its soft cushioning effect |
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The loose subcutaneous layer gives skin an __________ mobiity over structures underneath.
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- increased
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Epidermal appendages are formed by tubular invagination of the ________ down into the underlying __________.
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- epidermis
- dermis |
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Hair is _________ for humans.
- no longer needed for protection from cold or trauma --> little or no use/from ancestors |
- vestigial
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* Vellus hair:
- Does not cover which parts of the body? |
(epidermal appendage)
fine, faint hair covers most of the body - palms, soles, dorsa of the distal part of fingers, umbilicus, glans penis, inside labia |
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* Terminal hair:
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(epidermal appendage)
- darker, thicker hair - grows on: scalp, eyebrows, after puberty on axillae, pubic area, face and chest on males |
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* Sebaceous glands:
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(epidermal appendage)
- produce protective lipid substance, sebum --> secreted through hair folicle - sebum oils/lubercates skin and hair --> forms emulsion with water that retards water loss from skin - Everywhere but palms/soles - Most abundant: scalp, forehead, face, chin |
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* Sweat glands (2):
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(epidermal appendage)
- eccrine gland - apocrine gland |
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* Eccrine:
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(epidermal append: sweat gland)
- coiled tubules --> open directly onto skin and produce dilute saline solution, sweat - mature in 2 month old infant |
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* Apocrine:
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(epidermal append: sweat gland)
- produce thick, milky secretion --> open into the hair follicle - mostly in the auxillae, anogenital area, nipples and naval (vastigial in humans) - acitve during puberty, emotional, sexual stimulation - bacteria flora --> musky body oder on surface of skin - decreases function in aging adult |
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* Nails:
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(epidermal appendage)
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