A&P Chapter 5 – Flashcards
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What are the three major regions of the skin?
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epidermis, dermis, and hypodermis
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the outermost superficial region of the skin
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epidermis
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the middle region of the skin
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dermis
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the deepest region of the skin
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hypodermis(superficial fascia)
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composed of keratinized stratified squamous epithelium, consisting of four distinct cell types and four or five layers; the outer portion of the skin that is exposed to the external environment and functions in protection
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epidermis
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the four distinct cell types of the epidermis
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keratinocytes, melanocytes, Merkel cells, and Langerhan's cells
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produce the fibrous protein keratin
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keratinocytes
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produce the brown pigment melanin
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melanocytes
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epidermal macrophages that help activate the immune system
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Langerhan's cells
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function as touch receptors in association with sensory nerve endings
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Merkel cells
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the deepest epidermal layer firmly attached to the dermis; consists of a single row of the youngest keratinocytes
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basal layer
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the innermost layer of the epidermis; the alternate name of basal layer
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stratum germinativum
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when cells undergo rapid divison
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mitosis
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cells contain a weblike systemof intermediate filaments attached to desmosomes; melanin granules and Langerhans' ll are abundant in this layer
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stratum spinosum/prickly layer
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basal layer of the epidermis
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Stratum Basale
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prickly layer of the epidermis
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Stratum Spinosum
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granular layer of the epidermis
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Stratum Granulosum
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clear layer of the epidermis
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Stratum Lucidum
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Thin; three to five cell layers in which drastic changes in keratinocyte appearance occurs; keratinocytes flatten, nuclei and organelles begin to disintergrate,accumulate keratohyaline and lamellated granules; lamellated granules contain a waterproofing glycolipid
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Stratum Granulosum/Granular Layer
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thin layer found only in thick skin(soles of feet); thin, transparent band superficial to the stratum granulosum; consists of a few rows of flat, dead keratinocytes; present only in thick skin
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Stratum Lucidum/Clear Layer
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outermost layer of keratinized cells; accounts for three quarters of the epidermal thickness
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Stratum Corneum
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Three functions of the Stratum Corneum
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waterproofing, protection from abrasion and penetration, and rendering the body relatively insensitive to biological, chemical, and physical assaults
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second major skin region containing strong, flexible connective tissue
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dermis
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cell types of the dermis
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fibroblasts, macrophages, and occasionally mast cells and white blood cells
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the two layers of the epidermis
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papillary and reticular
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layer of the epidermis responsible for 20% of the thickness of skin
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papillary layer
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layer of the epidermis responsibe for 80% of thickness of skin
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reticular layer
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subcutaneous layer deep to the skin; composed of adipose and areolar connective tissue
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hypodermis
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skin pigment that protects humans from UV radiation
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melanin
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the three pigments that contribute to skin color
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melanin, carotene, and hemoglobin
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yellow to reddish-brown to black pigment, responsible to dark skin colors
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melanin
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result from local acumulations of melanin
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freckles and pigmented moles
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yellow to orange pigment, most obvious in the palms and soles of the feet
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carotene
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reddish pigment responsible for the pinkish hue of the skin
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hemoglobin
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the skin appendages; derivatives of epidermis
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nails, sweat glands(Sudoriferous Glands), Sebaceous(Oil) glands, hair follicles and hair
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Eccrine, Appocrine, Ceruminous(modified), and Mammary(modified) are examples of what type of gland:
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sweat glands(Sudoriferous Glands)
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Eccrine sweat glands are also called ______________.
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merocrine sweat glands
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glands found in palms, soles of feet, and forehead; simple, coiled, tubular gland; secretory part coiled part in dermis; duct extend to open in pore; true sweat, released in exocytosis; 99% water, also some salts, antibodies, mocrobe-killing peptide, metabolic wastes; thermoregulation
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Eccrine Sweat Glands
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glands located in th axillary and anogenital regions
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apocrine sweat glands
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oil glands
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Sebaceous Glands
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a modification of the epidermis; grows in density and is affected by nutrition and hormones; filamentous strands of dead keratinized cells; contains hard keratin which is tougher and more durable tan soft keratin of the skin; made up of the shaft projecting from the skin, and the root embedded in the skin; consists of a core called the medulla, a cortex, and an outermost cuticle; pigmented by melanocytes at the base
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Hair
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Functions of the hair include:
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helping to maintain warmth, alerting the body to presence of insects on the skin, guarding the scalp against physical trauma, heat loss, and sunlight
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Hair is distributed over the entire skin surface except ____, ____, ____, ____, and ____.
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palms, soles, lips, nipples, and portions of the external genitalia
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Oily secretion is called ______.
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sebum
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root sheath extending from the epidermal surface into the dermis
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hair follicle
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Two types of hair are ____ and ____.
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Vellus and Terminal
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pale, fine body hair; body hair of children and adult females
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Vellus
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coarse, long hair of eyebrows, scalp, axillary, and pubic regions; grows in response to the stimulating effects of male sex hormones called androgens
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Terminal
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male sex hormones
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androgens
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Hair growth and density are influenced by many factors, but most important by _____ and _____.
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nutrition and hormones
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hair thinning in both sexes
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alopecia
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The structure of a nail is a scalelike modification of the _____.
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epidermis
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Functions of the Integumentary System include ____, ____, ____, ____, ____, and ____.
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protection, body temperature regulation, cutaneous sensation, metabolic functions, blood reservoir, and excretion
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cooling of dermal vessels
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dilation
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warming of dermal vessels
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constriction
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helps us sense changes in environment; exteroceptors sense touch and pain
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cutaneous sensation
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The blood reservoir of the skin is found in the ____.
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dermis
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The epidermis does not have ________.
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blood vessels
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Skin blood vessels store up to __% of the body's blood volume.
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5
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the bodily process of discharging waste matter
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excretion
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Limited amounts of nitrogenous wastes are eliminated from the body in ____.
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sweat
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1 in __ Americans develops skin cancer at some point.
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5
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Most skin tumors are ____ and do not ____.
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benign; metastasize
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The crucial risk factor for skin cancer is overexposure to _________.
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UV radiation
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UV radiation damages _________ and disables the __________.
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DNA bases; p53 genes
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a tumor suppressor gene
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p53
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The three major types of skin cancer are ____, ____, and ____.
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basal cell carcinoma, squamous cell carcinoma, and melanoma
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__________ is 85% of skin cancer.
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Basal Cell Carcinoma
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The least malignant and most common skin cancer; slowly growing and do not often metastasize; can be cured by surgical excision in 99% of cases
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Basal Cell Carcinoma
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Skin cancer that arises from keratinocytes of stratum spinosum; arise most often on scalp, ears, and lower lip; grows rapidly and metastasizes if not removed; prognosis is good if treated by radiation therapy or removed surgically
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Squamous Cell Carcinoma
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the least common and most dangerous skin cancer
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Melanoma
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__________ is the most dangerous type of skin cancer because it is _________ and __________.
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Melanoma; highly metazoic and resistant to chemotherapy
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Melanomas have the follow characteristics: ABCD rule
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Asymmetry, Border, Color, and Diameter
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What protects you from the effects of the sun?
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melanin
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Chance of surviving Melanoma is poor if the lesion is over __ mm thick.
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4
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a type of burn where only the epidermis is damaged; symptoms include localized redness, swelling, and pain
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First-degree
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a type of burn where the epidermis and upper regions of dermis are damaged; symptoms mimic first degree burns, but blisters also appear
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Second degree
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a type of burn where the entire thickness of the skin is damaged; the body loses a lot of fluids; burned area appears gray-white, cherry red, or black; there is no initial edema or pain(since nerve endings are destroyed)
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Third-degree
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Severe burn complications include ____, ____, and ____.
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dehydration, electrolyte imbalance, and pathogens
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the leading cause of death in burn patients
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infection
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estimates the severity of burns
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Rule of Nines
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Burns are considered critical if over __% of the body has second-degree burns or over __% of the body has third-degree burns or there are third degree burns on face, hands or feet.
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25; 10
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downy coat of delicate hairs covering the fetus(month 5 of pregnancy)
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lanugo
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substance produced by sebaceous glands that protects the skin of the fetus in the amnion(month 5 of pregnancy)
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vernix caseosa
