Integumentary System Study Guide Questions – Flashcards
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Functions of integumentary system
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protection, thermoregulation, excretion, cutaneous sensation, vitamin D synthesis, blood reservoir
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2 layers of the skin
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epidermis & dermis
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hypodermis
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superficial fascia or subcutaneous layer
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location of hypodermis
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deep to the dermis
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Primary tissue types in hypodermis
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areolar & adipose
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Functions of hypodermis
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anchor skin to underlying organs, act as shock absorber, insulate deeper body tissues, contains major blood vessels that supply the skin
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Primary tissue type in the dermis
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dense irregular CT
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type of connective tissue fibers contained in dermis
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mostly collagen fibers, smaller amounts of elastic and reticular fivers
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types of cells commonly found in dermal layer
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numerous blood vessels
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Organs/structures located in dermis
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nerve fibers, sensory receptors, major portions of hair follicles, sebaceous & sweat glands
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Layers of the dermis
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reticular & papillary
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Superficial layer of dermis
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papillary layer
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Dermal layer that is composed primarily of areolar connective tissue
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papillary layer
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Dermal layer composed primarily of dense irregular connective tissue
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reticular layer
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Significance of dermal papilla
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point of contact between dermis & epidermis. secures anchoring
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How lines of cleavage are formed
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by separations between collagen bundles within the tissue. collagen bundles are arranged in parallel fashion and the breaks are called lines of cleavage
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Types of cells in epidermis
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keratinocytes, melanocytes, Langerhans' cells, Merkel cells
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Primary cell type of epidermis
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keratinocyte
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General function of keratinocyte
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produce keratin
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General function of melanocyte
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produce and release melanin, which then accumulates in superficial parts of keratinocytes
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General function of Langerhans' cells
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type of fixed macrophage — protects against bacterial invasion
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General function of Merkel cells
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serve as sensory receptors for touch
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5 layers of the epidermis from deep to superficial
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stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
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Difference in epidermal layers in appearance/function
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basale: single row of keratinocytes, melanocytes & Merkel cells present spinosum: 8-10 cell layers thick, keratocytes, tonofilaments, flattened and irregularly-shaped cells granulosum: thin layer, flattened cells, "grainy", keratohyalin granules & lamellar granules lucidum: only in "thick skin," cells are dead coreum: "horny layer" 20-30 layers shingle-like dead cell remnants completely filled w/ keratin
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layer not present in thin skin
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stratum lucidum
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Epidermal layer in which most mitosis occurs
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stratum basale
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Epidermal layer beyond which no mitosis occurs
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stratum spinosum
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Epidermal layer in which cells contain keratohyalin and lamellar granules
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stratum granulosum
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Functional significance of keratohyalin granules
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involved in formation of keratin. enzymes and proteins that cause prekeratin to become keratin.
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Functional significance of lamellar granules
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contain a glycolipid that, when secreted, helps to waterproof superficial layers of epidermis. slows water movement
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Epidermal layer in which tonofilaments first become evident
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stratum spinosum
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Epidermal layer in which you first expect to see significant amounts of keratin
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stratum corneum
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epidermal layer containing most melanocytes
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stratum basale
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Epidermal Layer in which cells begin to die
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stratum granulosum
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Epidermal Layer in which cells are dead
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stratum lucidum
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Body areas in which thick skin is located
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palms & soles
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Pigments that determine skin color
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melanin carotene hemoglobin
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Effects of chronic exposure to UV radiation on the skin
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destroys body's folic acid stores for DNA synthesis, heighten skin's sensitivity to UV radiation substantial melanin buildup, which protects DNA of viable skin cells from UV radiation
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Effect of sunlight on melanocytes
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stimulated to greater activity by chemicals secreted by surrounding keratinocytes when exposed
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albinism is most often associated with inability to synthesize what enzyme
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melanin
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Direct effect of deficiency of melanin
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Albinism- lack of pigmentation in skin, hair, and eyes
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Difference between root and shaft of an individual hair
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shaft: portion in which keratinization is complete. projects from skin & extends halfway down the portion embedded in the skin. root: keratinization still ongoing. remainder of the hair deep within the follicle
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Location and function of hair follicle
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folded down from the epidermal surface into the dermis. contains sensory nerve endings so hair can be a touch receptor
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Location and function of hair papilla
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nipplie-like bit of dermal tissue- protrudes into hair bulb. contains a knot of capillaries to provide nutrients and signal it to grow
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Location and function of matrix of hair follicle
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Composed of actively dividing cells in the hair bulb to produce hair. Pushes up old hair as new hair is produced
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Location and function of root hair plexus
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knot of sensory nerve endings wrapped around each hair bulb. Stimulates nerve endings to be a sensitive touch receptor
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Location and function of arrector pili muscle
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attaches to the hair follicle near the surface and pulls the follicle into an upright position
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Cause of arrector Pili contraction
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response to cold external temperature or to fear
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2 basic types of glands in integumentary system
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sweat (sudoriferous) and sebaceous (oil)
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Structure and function of sebaceous glands
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simple branched alveolar — all over the body except palms and soles. secrete sebum that softens and lubricates hair and skin
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Composition and function of sebum
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sebum softens and lubricates hair and skin, prevents hair from becoming brittle, and slows water loss from skin. bactericidal. forced out by arrector pili contractions. sebum contains oil
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2 main types of sudoriferous glands associated with the skin
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eccrine and apocrine
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Describe eccrine secretions
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sweat- hypotonic iltrate of the blood. 99% water, some salts, vitamin C, antibodies, microbe-killing peptide called dermcidin
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Describe apocrine secretions
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same basic components as sweat, + fatty substances and proteins. viscous and milky/yellowish color. odorless except when decomposed by bacteria
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Defining features of basal cell carcinoma
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originates in stratum basale least malignant, most common most likely to appear in body areas that receive chronic UV exposure
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Functional class of eccrine gland
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merocrine
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Defining features of squamous cell carcinoma
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Arises from keratinocytes of stratum spinosum Appears as small, rounded elevation Gros quickly, metastisizes if not detected/treated early
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Defining features of melanoma
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cancer of melanocytes least common, most dangerous grows rapidly and metastisizes through lymphatic system ~33% develop from pre-existing moles ABCDE rule
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ABCD(E) mneumonic
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Asymmetry Border (irregular or notched) Color (not homogenous) Diameter (bigger than pencil eraser) Elevation
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Burn
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tissue damage caused by intense heat, radiation, electricity, of certain chemicals. denaturation of proteins — cell death
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3 classes of burns
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1st degree 2nd degree 3rd degree
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General characteristics of 1st degree burns
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only epidermis is damaged symptoms include localized redness and swelling heals in 3-5 days mild sunburn "partial thickness" burn
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General characteristics of 2nd degree burns
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damage through epidermis into upper level of dermis symptoms include localized redness, swelling, pain, BLISTERS 3-4 weeks to heal if no infection "partial thickness"
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General characteristics of 3rd degree burns
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considered "full-thickness"- whole way through dermis appearance of burned area varies from grey/white to bright red to blackened marked swelling, no pain (nerve endings destroyed) significant fluid and electrolyte loss
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Which classes of burns are full thickness and which are partial thickness?
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1st & 2nd: partial 3rd: full
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Potential life-threatening systemic effects of severe burns
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-excessive fluid, electrolyte & plasma protein loss that leads to severe dehydration and electrolyte imbalance -potential for circulatory shock & renal failure -risk of bacterial infection
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Identify 4 steps involved in regeneration of tissue after injury
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1. inflammation 2. migratory phase 3. proliferative phase 4. maturation phase
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Describe inflammation in tissue healing
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-triggered by release of chemical mediators from local mast cells & damaged tissue cells. -blood clot forms if bleeding occurred -tissue debris is removed from area by phagocytes which have migrated there as a result of tissue damage
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Describe migratory phase in tissue healing
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-begins during inflammation, a few hours after injury -begins w/ migration of cells from STRATUM BASALE into area of injury. proliferate (mitosis) and form new epidermis -fibroblasts migrate and produce scar tissue -blood clot replaced by granulation. internally then works upward
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Describe proliferative phase in tissue healing
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-tissues and blood vessels continue to regenerate -scab detaches, epithelium thickens -everything continues to regenerate and phagocytic activity ends
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Describe maturation phase in tissue healing
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-scab is shed, epidermis is fully regenerated -fibroblasts decrease in number
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superficial fascia
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aka hypodermis. superficial to tough connective tissue wrapping of skeletal muscles (fascia), mostly adipose tissue
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subcutaneous layer
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hypodermis. acts as shock absorber and insulator
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tyrosinase
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enzyme that converts tyrosine to melanin
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jaundice
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"yellow cast" abnormal yellow skin tone signifying liver disorder in which yellow bile pigments accumulate in the blood and are deposited in body tissues
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erythema
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redness- may indicate embarrassment, fever, hypertension, inflammation, or allergy
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hirsutism
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excessive hairiness. results from adrenal gland or ovarian tumor that secretes abnormally large amounts of androgens
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rule of nines
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used to estimate volume of fluid lost and percentage of body surface burned. divides body into 11 areas that each account for 9%
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epidermal ridge
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formed when papillae lay atop larger mounds called dermal ridges and causes the overlying epidermis to form a ridge. increases friction and enhances gripping ability
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carotene
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yellow to orange pigment found in certain plant products such as carrots. accumulates in stratum coreum and in fatty tissue of the hypodermis
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hemoglobin
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crimson colored oxygenated pigment that causes pinkish hue in fair skin. Red blood cells circulating through dermal capillaries
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alopecia
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baldness — hairs are not replaced as fast as they are shed -coarse terminal hairs are replaced by vellus hair and hair becomes increasingly wispy
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ceruminous gland
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modified apocrine glands in the lining of the external ear canal. secretion mixes with sebum to form cerumen (earwax)
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tonofilament
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bundles of intermediate filaments found in the skeleton of keratinocytes. retain cell shape and resist tension forces
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cyanosis
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caused by poorly oxygenated hemoglobin, causing blood and Caucasian skin to look blue. often cause of heart failure and severe respiratory disorders
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male pattern baldness
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genetically determined, sex-influenced condition caused by delayed-action gene that "switches on" in adulthood and changes response of hair follicles to DHT (metabolite of testosterone) hairs do not emerge from follicles before shedding
