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Flashcards in Integumentary System Deck (42)

Tissue in epidermis

Keratinized stratified squamous epithelial


Tissue in dermis

fibrous connective tissue


Layers in epidermis

Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale


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)


Stratum Corneum

Superficial, 20-30 layers, protect deeper cells from environment and water loss, protect from abrasion and penetration


Stratum Lucidum

visible only in thick skin, just deep to stratum corneum, superficial to stratum granulosum, dead keratinocytes


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.


Stratum Spinosum

several layers thick, contain web-like system of intermediate pre keratin filaments attached to desmosomes, abundant melanosomes and dentritic cells.


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.


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


arrector pili muscle

smooth muscle attached to follicle, responsible for goose bumps


dermal papilla

superficial peglike projections in papillary layer of dermis, contain capilary loops, contribute to pain + touch.


hair papilla

protrudes into the hair bulb, contains knot of capillaries that supplies nutrients to the growing hair and signals it to grow


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



produce fibrous protein keratin, which forms most of the epidermis. tightly connected by desmosomes.



fibrous protein that helps give epidermis its protective properties.



epithelial cells turn to keratin.



spider shaped epithelial cells that synthesize the pigment melanin, found in stratum basale


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



Blue skin color, low oxygenation of hemoglobin



Redness - fever, hypertension, inflammation, allergy


Pallor (blanching)

paleness - anemia, low blood pressure, fear, anger



yellowing - liver disorder



inadequate steroid hormones in addison's disease



clotted blood beneath skin


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.


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.


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.


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.



hair thinning. terminal hairs are replaced by vellus hairs, and hair becomes wispier. happens after age 40


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.


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


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


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


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


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.


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)


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


rule of nines

head = 9%
upper limbs = 18%
trunk = 36%
perineum = 1%
lower limbs = 36%


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.


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.


decubitus ulcers / bedsores

results from pressure or pressure in combination with shear and or friction. occurs in sacrum, coccyx, heels or hips, but can also occur elbows, knees, ankles, or back of the cranium.

pressure applied to soft tissue so that blood flow to the soft tissue is completely or partially obstructed.