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54 Cards in this Set
- Front
- Back
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Outer epidermis |
Avascular, made of stratified squamous epithelial cells |
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Inner dermis |
Vascular, made up of connective tissue (two types) |
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Functions of integumentary system |
Protection Temperature regulation Excretion Production of vitamin D Sensory reception |
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Protection |
Cushions/insulates organs, skin is water resistant, pigment in skin protection from harmful UV radiation |
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Temperature regulation |
Capillary network and sweat glands regulate loss of heat |
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Excretion |
Urea, salts, and water loss through sweat (water/salt balance). |
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Production of vitamin D |
By exposure to light, epidermal cells synthesize vitamin D (needed to uptake Ca2+ in intestines) |
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Epidermis cell lifespan? Weight of skin? |
Cell lifespan 35 days 7% of body weight |
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Epidermal cell types |
Keratinocytes Melanocytes |
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Keratinocytes |
Get pushed up by new cells produced beneath. Produce keratin which fills their cytoplasm. Dead, flat sacks when approach skin surface. Most abundant. Held together by desmosomes. |
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Melanocytes |
Melanin tranfered to keratinocytes (via spider legs). UV light exposure increases melanocyte activity (more melanin made for UV protection) |
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5 layers of epidermis |
Stratum corneum Stratum lucidum (only in thick skin) Stratum granulosum Stratum spinosum Stratum basale |
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Stratum corneum |
Keratinized stratified squamous epithelial tissue. No blood vessels. Filled with keratin. Thicker in palms/feet. Shed 40 lbs in lifetime. |
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Stratum lucidum |
In thick skin only. Thin, translucent layer, cells look clear. No nuclei or cell outlines. Looks identical to stratum corneum above it. |
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Stratum granulosum |
Transition layer, stains dark. Cells begining process of keratinization. Keratinocytes beginning to degenerate by lysosomal activity. |
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Stratum spinosum |
Some mitosis takes place here. Keratinocytes have spine like extentions. Dendritic cells here (star shaped) |
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Dendritic cells |
Star shaped. Part of immune system. Engulf foreign matter. |
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Stratum basale |
AKA stratum germinativum Single layer of cells next to dermis. Mostly stem cells= keratinocytes, so active mitosis and cells moving up. Melanocytes found here (10-25% of cells in stratum basale). Melanin injected into keratinocytes |
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Dermis basic description |
<1mm to 6mm thick Highly vascularized Two layers: papillary and reticular |
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Papillary layer |
Loose (areolar) CT with thin collagen and elastic fibers, for attachment of epidermis and nourish epidermis (branching capillaries). Next to epidermis= dermal papillae (projections) which protrude by epidermis |
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Dermal papillae |
On palms/soles lie atop larger mounds called dermal ridges. These elevate the epidermis into friction ridges (=fingerprints and footprints). Sweat pores open along crests of friction ridges leave fingerprints (=sweat films) |
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Reticular layer |
Dense, irregular CT. Thick bundles of collagen fibers (strength) and elastic fibers (stretch/recoil) that run in different directions. Makes up 80%of the thickness of the dermis. |
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Extreme stretching and cleavage lines? |
Extreme stretching- stretch marks, tearing of collagen in dermis Cleavage lines (or tension lines) arrangement of collagen bundles surgeons cut along lines. |
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Reticular layer fun facts (3) |
Receptive site for pigments in tattoos. Bruising where blood escaped curculation. Suede leather in animal skin mainly reticular layer. |
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Hypodermis |
AKA subcutaneous layer or superficial fascia (not part of integument). Consists of areolar and adipose CT (mostly areolar). Anchors skin to structures (mostly muscle). |
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Adipose in hypodermis |
Insulates. Thickens with weight gain. Cellulite more common in females with fat arranged in columns. |
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Glands in skin |
Sweat glands (appocrine and eccrine) and sebaceous glands |
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Sweat glands |
Tubular shaped AKA sudoiferous glands. Approcrine associated with hair follicles. Eccrine in dermis and hypodermis. |
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Appocrine sweat glands |
Eccrine mode of secretion. Abundant in armpits and genital area- discharge into hair follicles. Functions begin at puberty (increased sex drive) Secretions may be pheromones. Water, fats, and proteins secreted smell when decomposed by bacteria on skin. |
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Modified appocrine sweat glands |
Ceruminous glands- in external ear. Make cerumen (earwax). Mammary glands- secrete milk after females give birth. |
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Eccrine sweat glands |
More numerous type. More abundant on palms, soles, and forehead. Not on lips or penis. Coiled tubular gland in deep dermis and hypodermis. Cools body |
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Sweat from eccrine sweat glands |
99% water, some salts (mostly sodium chloride), trace metabolic wastes (urea, ammonia, uric acid). Acidic- retards growth of bacteria on skin. Involved in evaporative cooling of the body. |
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Sebaceous glands |
Associated with hair follicles. Holocrine secretion. Secrete sebum (lipid) into hair follicle, conditions and lubricates hair/skin, prevents cracking, slows water loss. Has antibacterial agents which fight infection |
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Teenagers and sebaceous glands |
Teenagers produce so much sebum that ducts get blocked = blackhead. If infected by bacteria = pimple. Acne results as bacteria break down sebum into fatty acids, acids and bacteria induce inflammation. |
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Acne treatments |
Benzoyl peroxide treats inflammatory acne. Vitamin A derivatives - prevents blackheads. Antibiotics destroy bacteria. |
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What is hair and what are its parts? |
Composed of keratin (non-living). Hair papilla Hair bulb Hair root Hair shaft |
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Hair papilla |
Peg of CT with capillaries and nerves |
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Hair bulb |
Epithelial cells surrounds papilla |
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Hair root |
Anchors hair into skin, begins at hair bulb to halfway up skin, where organization of hair complete |
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Hair shaft |
From this halfway point to skin surface. Color due to melanocytes at papilla producing melanin |
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2 types of melanin |
1. Black brown color 2. Yellow rust color Both combine to form all hair colors. White hair - decrease in melanin production, air bubbles in shaft instead. |
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Arrector pilli muscle |
Bundle of muscle, involuntary Erects the hair (goosebumps) Extends diagonally from hair follicle to epidermis. |
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Receptors in skin |
Meissner's corpuscles Pacinian corpuscles |
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Meissner's corpuscles |
In papillary layer of dermis. Projects up into papillae Receptors of light touch |
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Pacinian corpuscles |
Spherical with onion like cocentric rings. In deep reticular layer of dermis Receptors of deep touch (sustained pressure) |
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Nails |
Keratinized (dead) tissue like skin and hair (modified epidermal cells) arranged into plates |
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Psoriasis |
Chronic inflammation due to overproduction of epidermal cells (scaly skin). 30 day turnover normal 3 day psoriasis May be autoimmune, triggered by bacteria. No cure. Treatment: UV radiation (increased cancer risk), ointments, drugs that get activated by UV light to slow epidermal growth |
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Aging |
Epidermis thins Dendritic cells decrease Reduced vitamin D Melanocyte activity declines Glandular activity and blood supply declines. Hair follicles thinner/absent Dermis thinner |
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Epidermis thins |
Basal cell activity decreases. More prone to infection/injury |
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Dendritic cells in aging |
Decrease by 50%, immune function decreases |
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Reduced vitamin d production |
Can weaken bones |
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Melanocyte activity declines |
Sunburn more likely |
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Glandular activity and blood supply declines |
Less sebum (dry skin), impaired perspiration (overheating more likely), lower blood supply to dermis minimizes body heat loss |
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Dermis thinner |
Sagging/wrinkling |
