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48 Cards in this Set
- Front
- Back
Functions of skin
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Protection-barrier to bacteria;cushioning
Thermoregulation- sweating to loose heat, hair to retain heat, blood supply to capillaries Sensation-heat, cold, itch, touch, pain Excretion and absorption-urea and ammonia Vitamin D production |
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cutaneous membrane
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aka skin, 2 layers. Superficial, thinner portion composed of pithelial tissue=epidermis. Deeper thicker connective tissue part=dermis
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subcutaneous layer
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aka hypodermis, deep to the dermis not part of skin composed of areolar and adipose tissues. storage for fat and large blood vessels that supply the skin.
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Keratin
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tough, fibrous protein that helps protect the skin and underlying tissues from heat, microbes, and chemicals.
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Keratinocytes
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90% of epidermal cells, form the protective layer. produce the protein keratin and lamellar granules which release a water-repellent sealant.
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Melanocytes
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8% of epidermal cells, deep in epidermis. produce the pigment melanin which provides protection from ultraviolet light
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Langerhans cells
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arise from red bone marrow and migrate to the epidermis, special type of white blood cell, release hystamines. participate in immune responses against microbes
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Merkel cells
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least numerous epidermal cells, located in the deepest layer where they contact the flattened process of a sensory neuron called a tactile (merkel) disc.
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Layering of the epidermis
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superficial to deep.
Stratum corneum Stratum lucidum -thick skin only Stratum granulosum Stratum spinosum Stratum basale |
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Thick skin
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palms, fingers, soles of feet
thick stratum spinosum and corneum, stratum lucidum is present, more dermal papillae (palm, finger,foot prints) |
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Stratum basale
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Deepest layer, stem cells are undergoing mitosis, replace lost skin cells. one row of cuboidal or columnar keratinocytes.
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Stratum spinosum
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cells bound by desmosomes support for the epidermis, some mitosis is occuring.
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Stratum granulosum
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cells become squamous, fill with keratin, produce lipids waterproofing (lamellar granules), apoptosis programmed cell death, cells are specialized for their function and no longer going through mitosis
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Stratum lucidum
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only in thick skin,, clear layer of dead cells
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Stratum corneum
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dead cells containing keratin, multiple layers of overlapping cells for protection, gradually lost off surface
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Dermis
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2nd deeper part of the skin composed mainly of connective tissue, blood vessels, nerves, glands, and hair follicles.
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Papillary layer
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1/5 of total dermal layer. areolar connective tissue.
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Dermal Papillae
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fingerlike projection of the papillary region of the dermis that may contain capillary loops (blood capillaries) some contain touch receptors called corpuscles of touch and free nerve endings. blood vessels in the dp reduce the distance to each cell...nutrients can reach the cells and waste doesn't accumulate
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Reticular layer
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deep layer of the dermis that is attached to the subcutaneous layer. dense irregular connective tissue, a few adipose cells, hair follicles, nerves, sebaceous glands and sudoriferous (sweat)glands.
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Capillary loops
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smooth muscle sphincters regulate blood flow. Normal conserve heat, blushing lose heat.
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Color of skin
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Melanin, hemoglobin, and carotene 3 pigments that create wide variety of skin colors.
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Hair
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aka pili, offers some protectin from injury and sun (head) decreases heat loss, protects eyes, ears, nose from foreign particles, sensing light touch
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hair shaft
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superficial portion of the hair which projects above the surface of skin
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hair root
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portion of hair deep to the shaft that penetrates into the dermis and sometimes into the subcutaneous layer.
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3 concentric layers of hair
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shaft and root have inner medulla layer, middle cortex, and the cuticle.
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hair follicle
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surrounds the root of the hair made up of an external root sheath and and internal root sheath together reffered to as an epithelial root sheath.
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bulb
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base of each hair follicle. houss the papilla of the hair (contains areolar tissue and blood vessels that nourish the growing hair. also contains a germinal layer of cells called the matrix.
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hair growth
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eash follicle goes through a growth stage and a resting stage. during growth cells of the matrix differentiate, keratinize and die as new cells are added at the base of the hair root it grows longer. after resting hair falls out and new hair begins to grow in its place.
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Sebaceous glands
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usually connected to hair follicles, secrete oil onto cuticle of hair. strengthen hair
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eccrine sweat glands
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sweat on to surface of skin, more common. located in the deep dermis sometimes the upper subcutaneous layer
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apocrine sweat glands
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sweat onto hair, armpits and groin, begin to function at puberty.
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Nails
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plates of tightly packed, hard, dead, keratinized epidermal cells.
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nail matrix
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deep to the nail root were cells divide by mitosis to produce growth
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nail root
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portion that is buried in a fold of skin
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epinychium
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aka cuticle a narrow band of epidermis that extends from and adheres to the margin of the nail wall
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hyponychium
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secures nail to fingertip
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nail growth
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cells divide by mitosis in the matrix, specialize into nail cells.
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superficial wounds
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only damage to the epidermis, doesn't bleed. cells in the stratum basale divide and migrate to cover the wound and the other layers are replaced from the stratum basale, a little pain b/c nerve projections in epidermis.
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deep wound healing
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when a wound extends to the dermis and subcutantious layer. 4 stages.
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Inflammatory phase
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blood clot forms, inflammation helps eliminate microbes, foreign material and dead cells. WBC, phagocytes migrate into area, blood vessels open up to get more blood flow to area.
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Migratory phase
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scab forms, migration of stratum basale, fibroblasts migrate, blood vessels grow. begins process of healing.
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Proliferative phase
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epithelial growth, random collagen, blood vessels grow.
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Maturation phase
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scab sloughs off. organized collagen, normal circulation.
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neutrophils
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phagocytic white blood cells. come during inflammatory phase
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monocyte
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develop into macrophages that phagocytize microbes. come during inflammatory phase
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first degree burn
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damage to epidermis
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second degree burn
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damage to dermis
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third degree burn
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damage to hypodermis and deeper tissues
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