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37 Cards in this Set
- Front
- Back
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The integumentary system consists of...
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Cutaneous membrane
- Epidermis - Dermis Accessory structures Subcutaneous layer |
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Accessory structures
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Hair
Nails Sweat glands |
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Integumentary system functions
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Protection
Excretion Temperature maintenance Nutrient storage Vitamin D3 synthesis Sensory detection |
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Thin skin/Thick skin
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The epidermis is composed of keratinocytes --
Thin skin = 4 layers (strata) Thick skin = 5 layers |
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Epidermis functions
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Provides mechanical protection
Prevents fluid loss Keeps microorganisms from invading the body |
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5 layers of the epidermis
(from deep to superficial) |
Stratum germinativum
Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum |
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Stratum corneum
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Found in thin & thick skin
15-30 layers of keratinocytes Cells are dead Tightly interconnected by desmosomes Cells shed in sheets or large groups Water resistant, not waterproof |
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Stratum lucidum
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"clear layer"
Found ONLY in thick skin of palms & soles Cells flattened, densely packed, & filled w/keratin Last layer of living cells |
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Stratum granulosum
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"grainy layer"
3-5 layers of keratinocytes Most cells have stopped dividing Cells making protein keratin & keratohyalin |
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Stratum spinosum
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"spiny layer"
8-10 layers of keratinocytes Contain Langerhans cells |
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Stratum germinativum
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Also called stratum basale
Innermost epidermal layer Forms epidermal ridges (i.e. fingerprints) Contain basal cells (germinative cells) Contain Merkel cells Contain melanocytes |
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Basal cells
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Stem cells whose divisions replace the more superficial keratinocytes that are lost or shed at the epithelial surface
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Merkel cells
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Specialized epithelial cells
Sensitive to touch When touched, released chemicals that stimulate sensory nerve endings Found on skin surfaces lacking hair |
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Langerhans cells
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Participate in the immune response by stimulating a defense against
1) microorganisms that manage to penetrate the superficial layers of epidermis, and 2) superficial skin cancer |
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Epidermal characteristics
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Cells accumulate keratin & eventually are shed
Epidermal ridges are interlocked w/dermal papillae -Fingerprints -Improve gripping ability Langerhans cells (immunity) in s. spinosum Merkel cells (sensitivity) in s. germinativum |
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Skin color depends on...
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Blood supply
Carotene & melanin -Melanocytes produce melanin & protect from UV radiation Epidermal pigmentation -Interrupted blood supply leads to cyanosis |
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Cyanosis
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Blue skin due to no blood or low blood oxygen
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1st degree burn
2nd degree burn 3rd degree burn |
Epidermis
Dermis Hypodermis ("cooking the fat") |
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Epidermal cells
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Synthesize Vitamin D3 (cholecalciferol) when exposed to UV
Respond to epidermal growth factor -Growth -Division -Repair -Secretion |
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The epidermis contains which type of tissue?
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Stratified squamous epithelium
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The dermis contains which types of tissue?
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Muscle, nervous, & connective
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Dermal organization
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Papillary layer
-Contains blood vessels, lymphatics, sensory nerves of epidermis Reticular layer -Contains network of collagen & elastic fibers to resist tension |
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Stretch marks
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Caused by excessive stretching of the dermis
Patterns of collagen & elastic fibers form lines of cleavage |
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Contains blood vessels
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Dermis - yes
Epidermis - no |
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Dermal circulation & innervation
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Cutaneous plexus arteries found in subcutaneous layer/papillary dermis
Cutaneous sensory receptors (light touch, pressure) |
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Hyperdermis
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Contains fat
Stabilizes skins position against underlying organs & tissues |
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Hair
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Originate in hair follicle
Composed of root & shaft Root base (hair papilla) surrounded by hair bulb & root hair plexus Hairs have soft medulla & hard cortex Cuticle = superficial dead protective layer Surrounded by epidermis & extends into dermis to level of subcutaneous |
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Hair types
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Vellus hairs (peach fuzz - baby)
Terminal hairs (heavy - head & pubis) Club hair (cessation of growth - beard, nostril, eyelashes) -Shed & grow according to hair growth cycle |
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Arrector pili muscle
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Attaches to hair
Causes hair to stand on end when frightened or cold |
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4 glands in the skin
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Sebaceous
Suderiferous Mammary Ceruminous |
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Sebaceous glands
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Discharge waxy sebum onto hair shaft when associated with hairs
Sebaceous follicles discharge onto epidermal surface |
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Suderiferous glands
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Apocrine sweat glands
-Produce odorous secretion -Location: groin, armpit Merocrine (eccrine) sweat gland -Sensible perspiration -Location: forehead, neck, back |
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Mammary glands
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Structurally similar to apocrine sweat glands
Location: breasts Secretion: milk |
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Ceruminous glands
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Location: external ear
Secretion: earwax |
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Nails
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Nail body covers the nail bed
Nail production occurs at the nail root Eponychium (cuticle) overlies root Free edge of nail extends over hyponychium |
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Local Control of Integumentary Function --
Injury & repair... |
Regenerates easily
Regeneration process includes formation of - Scab Granulation tissue Scar tissue |
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Aging & the Integumentary
System -- With age... |
Integument thins
Blood flow decreases Cellular activity decreases Repairs occur more slowly |
