Flashcards in Integumentary System Deck (42)
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Tissue in epidermis
Keratinized stratified squamous epithelial
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Tissue in dermis
fibrous connective tissue
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Layers in epidermis
Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale
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Cells in epidermis
Keratinocytes - most cells of epidermis, produce keratin, arise from basal layer
Melanocytes - 10-25% of cells in deepest epidermis, produce melanin (pigment), protect from UV
Dendritic langerhans cells - macrophages
Tactile cells (sensory)
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Stratum Corneum
Superficial, 20-30 layers, protect deeper cells from environment and water loss, protect from abrasion and penetration
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Stratum Lucidum
visible only in thick skin, just deep to stratum corneum, superficial to stratum granulosum, dead keratinocytes
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Stratum Granulosum
thin - 4-6 layers, cells flatten, nuclei and organelles disintegrate, keratinization begins. cells accumulate granules (keritahyaline (help form keratin) granules & lamellar (water resistant to slow water loss across epidermis). cells above this layer are too far from dermal capillaries and die.
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Stratum Spinosum
several layers thick, contain web-like system of intermediate pre keratin filaments attached to desmosomes, abundant melanosomes and dentritic cells.
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Stratum Basale
Deepest epidermal layer, also called germinative (highly mitotic). firmly attached to dermis. single row of stem cells. produces 2 daughter cells, 1 goes to surface, 1 remains in basal layer to continue reproducing.
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3 pigments that contribute to skin color
1. Melanin - only pigment made in skin, reddish-yellow to brownish-black, produced in melanocytes (same # in all ppl), migrates to keratinocytes to form pigment shields for nuclei. sunspots = not melanin, it's fungus infection. freckles & pigmented moles are local accumulations of melanin. sun exposure stimulates melanin production
2. Carotene - yellow to orange pigment, obvious in soles + palms. accumulates in stratum corneum + hypodermis. converts to vitamin A for vision and epidermal health
3. Hemoglobin - pinkish hue of fair skin
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arrector pili muscle
smooth muscle attached to follicle, responsible for goose bumps
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dermal papilla
superficial peglike projections in papillary layer of dermis, contain capilary loops, contribute to pain + touch.
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hair papilla
protrudes into the hair bulb, contains knot of capillaries that supplies nutrients to the growing hair and signals it to grow
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hair follicle
* extends from dermis to epidermal surface.
* has a 2 layered wall - part dermis, part epidermis
* hair bulb = deep end. contains hair papilla (capillaries) and sensory nerve endings.
* wall is composed of peripheral tissue sheath (dermis) and epithelial root sheath (epidermis).
* hair matrix produces hair cells, pushes upward
* arrector pili - muscle that causes goosy bumps
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Keratinocyte
produce fibrous protein keratin, which forms most of the epidermis. tightly connected by desmosomes.
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keratin
fibrous protein that helps give epidermis its protective properties.
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keratinization
epithelial cells turn to keratin.
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melanocyte
spider shaped epithelial cells that synthesize the pigment melanin, found in stratum basale
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melanin pigment
* only pigment made in skin,
* reddish-yellow to brownish-black,
* produced in melanocytes (same # in all ppl),
* migrates to keratinocytes to form pigment shields for nuclei.
* sunspots = not melanin, it's fungus infection.
* freckles & pigmented moles are local accumulations of melanin.
* sun exposure stimulates melanin production
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Cyanosis
Blue skin color, low oxygenation of hemoglobin
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Erythema
Redness - fever, hypertension, inflammation, allergy
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Pallor (blanching)
paleness - anemia, low blood pressure, fear, anger
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jaundice
yellowing - liver disorder
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Bronzing
inadequate steroid hormones in addison's disease
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Bruises
clotted blood beneath skin
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hair regions
medulla - central core, consists of large cells and air spaces. contains soft keratin, absent in fine hairs.
cortex - bulky layer surrounding medulla, consists of several layers of flattened skin.
cuticle - outermost layer, single layer of cells, looks like shingles.
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hair pigment
melanocytes at the base of the hair follicle, transferred to the cortical cells. various proportions of melanins of different colors combine to produce hair from blonde to black. red hair = iron containing pigment. when melanin production decreases and air bubbles replace melanin in the hair shaft, hair turns gray or white.
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distribution of hair (vellus vs terminal)
vellus = fine, pale. body hair of children and adult females.
terminal = coarser, longer. eyebrows, scalp. @ puberty, in axillary and pubic regions, and on face and chest of men.
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growth of hair
follicles cycle between active and regressive phases. average 2.25 mm growth per week, and loss of 90 scalp hairs daily. during regressive phase, hair matrix cells die and follicle base and hair bulb shrivel. hair falls out and a new hair grows.
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alopecia
hair thinning. terminal hairs are replaced by vellus hairs, and hair becomes wispier. happens after age 40
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true frank balding
aka male pattern baldness, genetically determined, sex-influenced condition. changes the response of the hair follicles to testosterone, and growth cycles become so short, the hair never makes it out of the follicle before shedding.
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structure of nails
* scalelike modifications of epidermis,
* protective cover for distal,
* dorsal surface of fingers and toes.
* contains hard keratin
* nail matrix is responsible for growth
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location, how many per person, types of sweat glands, and their structure
* all over body except nipples and parts of external genitalia.
* up to 3 million per person.
* eccrine + apocrine
* function of secretion: thermoregulation
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structure and location of sebaceous glands
* widely distributed except in palms and soles.
* develop from hair follicles and secrete into hair follicles
* remain inactive until puberty
* secrete sebum
* bacterial, softens hair & skin
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eccrine vs apocrine sweat glands
eccrine - abundant on palms, soles, forehead. simple, coiled, tubular gland. secretory part lies coiled in dermis, and duct extends to open in a pore at the skin surface. --secretion = sweat.
apocrine - in axillary and anogenial areas. larger, ducts empty into hair follicles. secrete sweat and fatty substances and proteins. --ear wax & milk from mammary glands. begin to function @ puberty
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Functions of Integumentary System PBCMBE
1. Protection
1. chemical - sebum + defensins, low PH retard bacterial multiplication; melanin
2. physical - thickness of skin, keratin & glycolipids block most water
3. biological - dendritic cells of epidermis, macrophages in dermis, DNA absorb UV radiation and turns it to heat
2. Body Temp Regulation - if temp rises, dilate dermal vessels and increase sweat activity. if temp lowers, capillaries constrict, skin temp drops to slow passive heat loss
3. Cutaneous sensation - detect temp, touch, pain
4. Metabolic functions - synthesize vitamin D and collagenase, convert carcinogens and activate some hormones.
5. Blood reservoir - up to 5% of body's blood volume
6. Excretion - nitrous wastes + salt in sweat.
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Skin cancers
Basal cell carcinoma - least malignant, most common. stratum basale cells grow and invade dermis & hypodermic. can be removed surgically.
Squamous cell carcinoma - second most common type, involves keratinocytes of stratum spinosum. scaly reddened papule on scalp, ears, lower lip, hands. does metastasize. can be removed with radiation therapy or removed surgically
Melanoma - most dangerous, cancer of melanocytes. highly metastatic and resistant to chemotherapy. people usually die. ABCD -- asymmetry, border irregularity, color (contains several), diameter (6mm)
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why are burns life threatening?
* catastrophic loss of body fluids containing proteins and electrolytes - causes dehydration and electrolyte imbalance, renal failure, circulatory shock (inadequate blood circulation due to reduced blood volume)
* also need thousands of extra food calories to replace lost proteins and allow for tissue repair.
* infection
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rule of nines
head = 9%
upper limbs = 18%
trunk = 36%
perineum = 1%
lower limbs = 36%
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Severity of burns
1st degree: only epidermis is damaged. redness, swelling pain. heal within 2-3 days. (sunburn)
2nd degree: epidermis and upper region of dermis is damaged. like 1st degree + blisters.
3rd degree: full thickness burns, involving entire thickness of skin. burned area is gray-white, cherry red, or blackened. nerve endings are not painful. needs skin grafting.
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Critical % of burns
25% of body has second degree burns
10% of body has third degree burns
There are third degree burns of face, hands, and feet.
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