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119 Cards in this Set

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Layer that is deep to the dermis but not part of the skin consisting of areolar & adipose tissue. Dermis anchors to this layer which in turn attaches to underlying fascia.
Subcutaneous layer (hypodermis)
What is the function of the subcutaneous layer?
Stores fat & contains blood vessels supplying skin.
Type of nerve ending found in the subcutaneous layer (& sometimes dermis) sensitive to pressure.
Pacinian (lamellated) corpuscles
What type of tissue composes the epidermis? (3 adjectives)
Keratinized stratified squamous epithelium
What are the 6 functions of the integumentary system?
Regulates body temperature, stores blood, protects body from external environment, detects skin sensations, excretes/absorbs substances, synthesizes vitamin D
What is the significance of the skin in relation to other organs?
It's the largest organ by surface area & weight.
Type of cell that makes up 90% of epidermal cells, arranged in 4-5 layers & produces keratin & lamellar granules.
Keratinocytes
Tough, fibrous protein that helps protect skin & underlying tissues from heat, microbes, & chemicals.
Keratin
A water-repellant sealant that decreases water entry/loss & stops entry of foreign materials. What type of cell produces it?
Lamellar granules produced by keratinocytes.
Type of cell making up 8% of epidermal cells & produces pigment melanin. Transfers melanin granules to keratinocytes. What layer is it found in?
Melanocytes. Found in deepest epidermal layer (basale).
What is the function of melanin?
It protects keratinocytes from UV light & contributes to skin colour.
Type of white blood cell found in epidermis that arises from red bone marrow & is involved in immune responses. Easily damaged by UV light. Monocyte (in blood) give rise to macrophage (WBC in tissue) which functions as phagocyte. What layer is it found in?
Langerhan cell. Found in stratum spinosum.
Least numerous type of epidermal cell. Connected to tactile disc (neuron) to detect touch sensations. What layer is it found in?
Merkel cell. Found in basale layer while projections found in stratum spinosum.
How many layers does the epidermis have in thin skin vs. thick skin?
Thin - 4 layers. Thick - 5 layers.
Name the 5 epidermal layers from superficial to deep.
Stratum: Corneum, lucidum, granulosum, spinosum, basale (germinativum)
Epidermal layer composed of simple cuboidal/columnar keratinocytes. Includes mitotic stem cells. Intermediate filaments called ___ make up the cytoskeleton of cells in this layer.
Stratum basale. Tonofilaments.
What is the function of tonofilaments in keratinocytes?
Attach to desmosomes of cells in basale & spinosum layer to bind them together. Also attaches to hemidesmosomes which bind the cell to basement membrane.
Transfer of a healthy patch of skin taken from a donor site to cover wound.
Skin graft
Procedure where small amount of patient's epidermis is removed & grown in lab to produce thin sheet of skin & transplanted back.
Autologous skin transplantation
Epidermal layer arranged in 8-10 layers of keratinocytes providing strength & flexibility to skin. Superficial to stratum basale.
Stratum spinosum
Epidermal layer made of 3-5 layers of flattened keratinocytes undergoing apoptosis. Keratohyalin converts tonofilaments into keratin. Lamellar granules secrete oily, water-repellant sealant.
Stratum granulosum
Epidermal layer present only in thick skin such as fingertips, palms, soles. Consists of 3-5 layers of dead keratinocytes w/ large amount of keratin & thickened plasma membrane.
Stratum lucidum
Epidermal layer made of 25-30 layers of dead keratinized stratified squamous epithelial cells that continuously shed & are replaced by deeper cells.
Stratum corneum
Abnormal thickening of stratum corneum due to constant exposure of skin to friction.
Callus
Accumulation of keratin, occurs as cells move from deepest to surface layer, is known as ___. What is the cycle duration?
Keratinization. 28 days.
Excess of keratinized cells shed from scalp.
Dandruff
If the epidermis is avascular, where does it get its nutrients?
Blood vessels in the dermis supply the stratum basale, which is the most active layer as it does mitosis.
Skin disorder where keratinocytes shed prematurely in 7-10 days & make abnormal keratin. Treatment includes ointment & UV phototherapy which decreases cell division, rate of cell growth, inhibits keratinization.
Psoriasis
What 4 structures are found in the dermal layer that are not in the epidermis?
Blood vessels & nerves (papillary region), glands & hair follicles (reticular region)
Which layer (epidermis/dermis) has great tensile strength & demonstrates extensibility, elasticity?
Dermis
What is the predominant type of cell in the dermis?
Fibroblast (some macrophages, adipocytes near subQ layer)
What type of tissue makes up the papillary region?
Loose areolar connective tissue (collagen, elastin, reticulin)
Small fingerlike structures that project into undersurface of epidermis. Increase surface area b/w dermis & epidermis.
Dermal papillae
Blood vessels found in dermal papillae are called ___.
Capillary loops
Tactile receptors sensitive to touch found in dermal papillae are called ___. Also found are ___, dendrites with no structural specialization (detect warmth, coolness, pain, tickling, itching).
Meissners corpuscles. Free nerve endings.
What type of tissue makes up the reticular region?
Dense irregular connective tissue (collagen)
Small tears in dermis from extreme stretching visible as red or silvery white streaks on skin surface.
Striae (stretch marks)
"Tension lines" in skin indicating predominant direction of underlying collagen fibers. Important to plastic surgeons as incision running parallel leaves a finer scar.
Lines of cleavage
Series of ridges & grooves found on palms, fingers, soles & toes that form fingerprints (& footprints). What is their function?
Epidermal ridges increase surface area which increases firmness of grip by increasing friction.
Study of pattern of epidermal ridges.
Dermatoglyphics
Melanin accumulating in flat patches can be either ___ or ___.
Freckles or age (liver) spots
Benign localized overgrowth of melanocytes.
Nevus (mole)
Melanin is synthesized from the amino acid ___ & enzyme ___.
Tyrosine (amino acid). Tyrosinase (enzyme).
Organelle in melanocytes that synthesize melanin.
Melanosome
A yellow-red or brown-black pigment produced by melanocytes which absorbs UV radiation, prevents damage to cell DNA, neutralizes free radicals.
Melanin
Oxygen-carrying pigment in red blood cells.
Hemoglobin
Yellow-orange pigment found in stratum corneum, dermis, subcutaneous layer.
Carotene
Condition of inherited inability to produce melanin.
Albinism
Condition of partial or complete loss of melanocytes from patches of skin.
Vitiligo
Buildup of yellow pigment bilirubin (byproduct of RBC destruction). May indicate liver condition.
Jaundice
Bluish skin caused by bad circulation.
Cyanosis
Pale skin caused by lack of hemoglobin.
Pallor
Redness of skin caused by engorgement of capillaries in dermis with blood due to skin injury, heat exposure, infection, inflammation, allergic reactions.
Erythma
Permanent coloration of skin in which a foreign pigment is deposited into dermis.
Tattoo
Insertion of jewelry through an artificial opening.
Body piercing
What is the function of hair (pili)?
Protection (UV rays, foreign particles), decreases heat loss, senses light touch.
Superficial portion of hair.
Shaft
Portion of hair deep to shaft that penetrates dermis (& sometimes subcutaneous layer)
Root
What are the 3 layers of cells in the hair from deep to superficial?
Medulla, cortex, cuticle.
In the epidermis, what 2 layers make up the hair follicle?
External root sheath (continuation of epidermis) & internal root sheath (known together as epithelial root sheath).
In the dermis, the dense area surrounding the hair follicle is known as ___.
Dermal root sheath
Structure at the base of each hair follicle & surrounding dermal rooth sheath. What does it contain?
Bulb contains hair matrix (basale cells, melanocytes) & papilla of hair (protrusion into matrix for capillaries).
What epidermal layer do the hair matrix cells arise from?
Stratum basale
Name 3 types of hair removal treatments.
Depilatory, electrolysis, laser treatment
Type of simple, branched acinar gland that is connected with hair follicles & secretes sebum (oil).
Sebaceous (oil) gland
Smooth muscle extending from dermis to dermal root sheath around side of hair follicle.
Arrector pili
Dendrites of neurons surrounding each hair follicle that are sensitive to touch.
Hair root plexuses
What are the 3 stages of the hair growth cycle?
Growth, regression, resting stage
Condition of partial or complete lack of hair (may result from genetic factors, aging, endocrine disorders, chemotherapy, skin disease).
Alopecia
Treatment of disease by means of agents that interrupt life cycle of rapidly dividing cancer cells.
Chemotherapy
Fine, nonpigmented hair in fetus.
Lanugo
Long, coarse heavily pigmented hair.
Terminal hair
Short, fine nonpigmented hair (peach-fuzz)
Vellus hair
What determines hair colour?
Type of melanin. Dark - eumelanin. Red/blond - pheomelanin.
Condition of excessive body hair in females or prepubertal males.
Hirsutism
What are 4 functions of sebum (secreted by sebaceous glands)?
Prevents hair from drying, prevents water evaporation on skin, keeps skin soft, inhibits growth of some bacteria.
Inflammation of sebaceous glands that usually begins at puberty when gland is colonized by bacteria is called ___. Infection that can cause a cyst to form & can permanently scar the epidermis is called ___. Treatment includes mild soap, topical/oral antibiotics, topical drugs.
Acne. Cystic acne.
___ glands are divided into 2 main types based on structure, location, type of secretion.
Sudoriferous (sweat)
Simple coiled tubular glands found mostly in dermis that excrete mostly water, salt, urea (also ammonia, amino acids, glucose, lactic acid) to regulate body temperature in process called ___. Also plays a small role in eliminating wastes. Also stimulated during emotional stress.
Eccrine sweat gland. Thermoregulation.
What's the difference between insensible & sensible perspiration?
Insensible - evaporates before it's seen as moisture on skin. Sensible - seen as moisture on skin.
Type of sweating that first occurs on palms, soles, axillae in response to emotional stress.
Emotional sweating (cold sweat)
Type of sweat gland found mostly in subcutaneous layer activated during puberty that includes lipid/protein content. Present in secondary sex regions & opens into hair follicles. Odorless until it reacts w/ bacteria on skin surface. Stimulated during emotional stress, sexual excitement.
Apocrine sweat gland
Type of gland found in subcutaneous layer that secretes cerumen, a waxy secretion that provides a sticky, waterproof barrier that prevents entry of foreign bodies into ear canal.
Ceruminous gland
What type of cells form nails?
Tightly packed, hard, keratinized epidermal cells.
Visible portion of nail that doesn't shed. Appears pink because of blood flow underneath.
Nail body
Part of nail body that extends past distal end of digit. Appears white because there are no underlying capillaries.
Free edge
Whitish, cresent-shaped area of proximal end of nail body. Vascular tissue doesn't show underneath due to thickened region of epithelium.
Lunula
Thickened region of stratum corneum beneath free edge that secures nail to fingertip.
Hyponychium (nail bed)
Narrow band of epidermis that occupies proximal border of nail and consists of stratum corneum.
Eponychium (cuticle)
Proximal portion of epithelium deep to nail root where cells divide by mitosis to produce growth.
Nail matrix
What factors affect the rate of nail growth?
Age, health, nutrition, season, time, temperature.
Dermis houses 8-10% of total blood flow in adult so it acts as a ___ ___.
Blood reservoir.
What volume of water evaporates through skin daily? (doesn't include sweat)
400 mL
What type of materials can be absorbed through the skin?
Fat-soluble vitamins (A,D,E,K), certain drugs, gases oxygen/carbon dioxide. Toxic substances: organic solvents - acetone, carbon tetrachloride, salts of lead, mercury, arsenic, poison ivy/oak, topical steroids.
Type of drug administration that enables drug in adhesive skin patch to pass across epidermis into blood vessels. Can be released at a controlled rate over period of several days.
Transdermal drug administration
Most active form of vitamin D that aids in calcium absorption. Requires 10-15mins 2x a week exposure to UV light to synthesize vitamin D.
Calcitriol
What are the steps in epidermal wound healing?
1) Basal cells surrounding wound enlarge & migrate from opposite sides of wound until they meet. 2) Stop migrating due to contact inhibition. 3) Epidermal growth factor hormone stimulates basal cells to divide & replace.
What are the 4 phases of deep wound healing in order?
Inflammatory, migratory, proliferative, maturation.
Deep wound healing phase where blood clot forms & inflammation occurs to eliminate microbes, foreign material, dying tissue in prep for repair. Fibroblasts, neutrophils, macrophages migrate to help repair.
Inflammatory phase
Deep wound healing phase where clot becomes scab & epithelial cells migrate beneath to bridge wound. Fibroblasts synthesize scar tissue & damaged blood vessels regrow. Granulation tissue fills wound.
Migratory phase
Deep wound healing phase characterized by extensive growth of epithelial cells beneath scab, fibroblast deposit collagen fibers in random patterns, continued blood vessel growth.
Proliferative phase
Deep wound healing phase where scab falls off, collagen fibers become more organized, fibroblast numbers decrease, blood vessels restored.
Maturation phase
Process of scar tissue formation.
Fibrosis
How is scar tissue different from normal skin?
Collagen fibers more dense, decreased elasticity, fewer blood vessels, may have less hairs, skin glands, sensory structures.
Why are scars usually lighter in colour than normal skin?
Arrangement of collagen fibers & less blood vessels.
What is the difference b/w a hypertropic vs. keloid scar?
Hypertrophic remains in same boundaries as original wound. Keloid extends beyond boundaries into normal tissue.
Would an epidermal wound bleed?
No because epidermis is avascular.
Epidermis is derived from which embryonic tissue?
Ectoderm
Substance that protects fetus from exposure to amniotic fluid & aids in birth because it's slippery. Composed of sebaceous glands, sloughed off peridermal cells, hairs.
Vernix caseosa
In the fetus, the dermis arises from ___ which gives rise to ___ that differentiate into fibroblasts.
Mesoderm. Mesenchyme.
Skin condition that affects mostly light skinned adults b/w 30-60. Redness, tiny pimples, noticeable blood vessels usually in central face.
Rosacea
(UVA/UVB) ray makes up 95% of UV radiation reaching earth. Not absorbed by ozone layer. Penetrate farthest into skin & absorbed by melanocytes. (UVA/UVB) ray partially absorbed by ozone layer, don't penetrate skin as deeply, cause sunburn, cause most tissue damage.
UVA. UVB.
Caused by exposure to UV radiation. A heightened reaction of skin after consumption of certain meds/contact with substances. Redness, itching, blistering, peeling, hives, shock.
Photosensitivity
What are 5 risk factors for skin cancer?
Skin type, sun exposure, family history, age, immunological status.
List 3 common type of skin cancer.
Basal cell (78%) & squamous cell (20%) carcinoma. Malignant melanoma (2%, deadly) arise from melanocytes.
Name 5 systemic effects of a major burn which are a greater threat to life than local effects.
1) Large loss of water, plasma, plasma proteins will cause shock. 2) Infection. 3) Reduced blood circulation. 4) Decreased urine production. 5) Decreased immune response.
Conditon caused by shedding of epithelium caused by constant deficiency of blood flow to tissue. Usually develop in tissues overlying bony projections subjected by pressure, such as shoulders, hips, buttocks, heels, ankles.
Pressure ulcer
Describe aging effects on the skin.
Most occur in dermis. Collagen fibers decrease & disorganize. Elastic fibers lose elasticity. Fibroblasts decrease. All result in wrinkles. Langerhans cells decrease. Macrophages become less effective. Decrease sebaceous glands leads to dry, broken skin susceptible to infection. Sweat production decreases. Less melanocytes = gray hair, abnormal skin pigmentation. Larger melanocytes = age spots. Hair loss. Blood vessels thicker. SubQ adipose tissue lost. Skin heals poorly. Decrease skin thickness. Hair/nail growth decreases.
In the rule of nines method of measuring extent of burns, what is each body part worth? Head, trunk, upper and lower limbs, perineum.
Numbers must be doubled to account for ant vs post aspect. Head 4.5%, upper limb 4.5% each, trunk 18%, lower limb 9%, perineum 1%.