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117 Cards in this Set
- Front
- Back
2 distinct regions of skin and the subcutaneous region deep to the skin
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epidermis
dermis hypodermis |
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another name for hypodermis; consists mostly of adipose tissue; not technically part of skin
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superficial fascia
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3 functions of hypodermis
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1) insulate
2) shock absorber 3) anchors skin to underlying structures |
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epidermis tissue type
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keratinized stratified squamous epithelium
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4/5 layers of epidermis
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1) stratum basale
2) stratum spinosum 3) stratum granulosum 4) stratum lucidum (in thick skin) 5) stratum corneum |
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4 epidermal cell types
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1) keratinocytes
2) melanocytes 3) epidermal dendritic cell (Langerhans' cells) 4) tactile cells (Merkel cells) |
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the keratinized stratified squamous epithelium consisting of 4 cell types and 4/5 layers
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epithelium
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fibrous protein that helps give the epidermis its protective properties
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keratin
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location of keratinocytes
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stratum basale
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spider-shaped epithelial cells that synthesize pigment melanin
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melanocytes
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location of melanocytes
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stratum basale
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melanin granules are taken up to the superficial side of the skin by
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keratinocytes
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arise from bone marrow and migrate to the epidermis
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epidermic dendrite cells
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epidermic dendrite cells AKA
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Langerhans' cells
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ingest foreign substances and are key activators of our immune system; slender processes extend among the surrounding keratinocytes, forming a continuous network
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epidermic dendrite cells; Langerhans' cells
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tactile cells AKA
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Merkel cells
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cells present at the epidermal-dermal junction; associated with nerve ending; sensory receptor for touch
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tactile (Merkel) cell
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thick skin special layer and location
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stratum lucidum; between stratum corneum and stratum granulosum
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layer consists of single row of stem cells, continually renewing
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stratum basale
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several layers thick; contain intermediate filaments; contain spiny-looking desmosomes
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stratum spinosum
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thin layer; 3-5 layers; process of keratinization begin
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stratum granulosum
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cells flatten and nuclei and organelles disintegrate and accumulate two types of granules
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keratinization
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consists of 2 or 3 rows of clear, flat, dead keratinocytes with indistinct boundaries
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stratum lucidum
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outermost layer; consists of 20 to 30 cell layers; accounts for 3/4 of epidermal thickness
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stratum corneum
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stratum corneum 2 functions
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protects and waterproofs
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made of strong, flexible connective tissue
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dermis
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4 cells found in the dermis
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1) fibroblasts
2) macrophages 3) mast cells (occasionally) 4) white blood cells (occasionally) |
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two layers of the dermis
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1) papillary layer
2) reticular layer |
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consists of areolar connective tissue, collagen and elastic fibers, and small blood vessels
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papillary layer
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indent the overlying epidermis
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dermal papillae
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most dermal papillae contain
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1) capillary loops
2) free nerve endings (pain receptors) 3) touch receptors |
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touch receptors AKA
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Meissner's corpuscle
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on hands and feet papillae lie in mounds called
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dermal ridges
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collectively skin ridges are called
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friction ridges
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genetically determined; sweat pores result in leaving these marks
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fingerprints
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accounts for 80% of the dermis; deepest layer of the dermis
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reticular layer
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collagen fibers mostly run ______ to skin surface
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parallel
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separation (less dense bundles of collagen fibers) between these bundles externally invisible lines run longitudinally in the skin of head and limbs and in circular patterns around neck and trunk
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cleavage lines or tension lines
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incision heals more readily when incision made ______ to cleavage lines
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parallel
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fibers that give the dermis skin strength and resiliency
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collagen fibers
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fibers that provide stretch-recoil properties of the skin
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elastic fibers
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dermal folds occur at or near joints; deep creases form
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flexure line
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3 pigments that contribute to skin color
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1) melanin
2) carotene 3) hemoglobin |
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pigment color ranges from yellow to tan to reddish-brown to black
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melanin
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synthesis of this pigment depends on enzyme in melanocytes; passes from melanobytes to basal keratinocytes
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melanin
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local accumulations of melanin
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freckles and pigmented nevi (moles)
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yellow to orange pigment most obvious in palms and soles
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carotene
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pinkish hue of fair skin result of this pigment
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hemoglobin
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5 skin appendages
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1) nails
2) sweat glands 3) sebaceous (oil) glands 4) hair follicles 5) hair |
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key component in forming skin appendages
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epithelial bud
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sweat glands AKA
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sudoriferous glands
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T/F Sweat glands are distributed over the entire skin surface except nipples and parts of external genitalia.
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true
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eccrine sweat glands AKA
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merocrine sweat glands
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glands more numerous and abundant in palms, soles of feet, and forehead
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eccrine sweat glands
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secretory part of eccrine sweat gland lies coiled in dermis and duct extends to open in a funnel-shaped ____ at skin surface
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pore
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sweat consists of (W2DAVS)
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1) 99% water
2) some salts (mostly NaCl) 3) vitamin C 4) antibodies 5) dermcidin 6) metabolic wastes |
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microbe-killing peptide found in sweat
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dermcidin
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sweating regulated by
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sympathetic division of autonomic nervous system
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major role of sweat
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thermoregulation of the body
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sweat glands confined to axillary and anogenital areas of body
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apocrine sweat glands
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apocrine sweat glands located
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deeper in dermis than eccrine sweat glands or in hypodermis
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apocrine sweat glands' ducts empty into _____ _______
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hair follicles
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components of apocrine secretion
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same as eccrine + fatty substances and proteins
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apocrine glands begin functioning
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at puberty
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modified apocrine glands found in the lining of the external ear canal
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ceruminous glands
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specialized sweat glands that secrete milk
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mammary glands
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simple, branched alveolar glands found all over body except thick skin; small on body, but large on face, neck, and upper chest
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sebaceous (oil) glands
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oil glands secrete an oil-filled substance called
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sebum
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cells accumulate oily lipids until they burst--_____ gland
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holocrine gland
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sebaceous glands develop from
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hair follicle
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what softens and lubricates the skin
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sebum
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most important role for sebum
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bactericidal (bacteria-killing)
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T/F Sebaceous glands are relatively inactive until puberty
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true
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Hairs are distribuited over entire skin surface except
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palms, soles, lips, nipples, parts of external genitalia
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main function of hair in humans
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sense insects
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hair on scalp guards against
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physical trauma, heat loss, and sunlight
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hair AKA
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pili
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hair largely consists of
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dead, keratinized cells
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hard keratin in hair advantages over soft keratin in epidermal cells
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1) tougher and more durable
2) individual cells don't flake off |
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3 layers of keratinized cells in hair
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1) central core--medulla
2) cortex 3) cuticle |
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hair pigment made by
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melanocytes
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red hair colored by iron-containing pigment called
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trichosiderin
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grey or white hair results from
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decreased melanin production
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responsible for producing goose bumps in cold or fear
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arrector pili muscle
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body of hair of children and adult females is pale, fine hair called
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vellus hair
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coarse, longer hair of eyebrows, pubic area, male face chest
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terminal hair
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each hair follicle goes 3 phases
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1) growth phase--weeks to years
2) regressive phase--hair matrix dies 3) resting phase--1-3 months |
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life span of hair under control of
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proteins
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follicles of scalp remain active for
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6-10 years til become inactive for few months
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follicles of eyebrow remain active for
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3-4 months
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thinning or degree of baldness
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alopecia
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true baldness caused by genetically determined sex-influenced condition
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male pattern baldness
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gene for male pattern baldness switches on in adulthood and changes response of hair follicles
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DHT
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3 types of barriers of skin
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1) chemical
2) physical 3) biological |
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low pH of skin secretions slows multiplication of bacteria
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acid mantle
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biological barriers of skin include (3)
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1) dendritic cells of epidermis
2) macrophages of dermis 3) DNA |
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6 functions of integumentary system (BMBEPC)
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1) body temperature regulation
2) metabolic function 3) blood reservoir 4) excretion 5) protection 6) cutaneous sensation |
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3 cutaneous sensory receptors
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1) messner's corpuscles
2) tactile discs 3) pacinian corpuscles |
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______in dermal papillae and ______ allow us to become aware of feeling of our clothing on our skin
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meissner's corpuscles; tactile discs
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in deeper dermis and hypodermis alert to deep pressure
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pacinian corpuscles
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when sunlight bombards the skin, modified cholesterol molecules circulating through dermal blood vessels are converted to
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vitamin D
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protein produced by skin cells and aids in natural turnover of collagen (deters wrinkles)
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collagenase
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dermal vascular supply can hold ___% of body's entire blood volume
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5%
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skin excretes
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nitrogen-containing wastes (ammonia, urea, uric acid), water and salt
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T/F Most of the tumors in the body are not benign and spread to other areas of the body
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false
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2 risk factors for skin cancer
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1) overexposure to UV rays
2) frequent irratations of the skin |
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least malignant of skin cancer; full surgical excision is used; accounts for nearly 80% of skin cancer
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basal cell carcinoma
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second most common type of skin cancer arises from keratinocytes of the stratum spinosum
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sqamous cell carcinoma
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most dangerous skin cancer; highly meastatic; surgical incision followed by immunotherapy
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melanoma
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ABCD rule for recognizing melanoma
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Assymetry
Border irregularity Color Diameter |
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burn where only the epidermis is damaged
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first-degree burn
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burn injuring the epidermis and upper region of the dermis
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second-degree burn
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full thickness burn involving entire thickness of skin
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third-degree burn
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epidermis develops from
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embryonic ectoderm
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dermis and hypodermis develop from
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mesoderm
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scaling and various kinds skin inflammation
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dermatitis
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in older age rate of _________ slows and skin ________, making bruising easier
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epidermal cell replacement; thins
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