The Integumentary System Flashcards

Terms Definitions
Functions of skin
Protection-barrier to bacteria;cushioningThermoregulation- sweating to loose heat, hair to retain heat, blood supply to capillariesSensation-heat, cold, itch, touch, painExcretion and absorption-urea and ammoniaVitamin D production
cutaneous membrane
aka skin, 2 layers. Superficial, thinner portion composed of pithelial tissue=epidermis. Deeper thicker connective tissue part=dermis
subcutaneous layer
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.
tough, fibrous protein that helps protect the skin and underlying tissues from heat, microbes, and chemicals.
90% of epidermal cells, form the protective layer. produce the protein keratin and lamellar granules which release a water-repellent sealant.
8% of epidermal cells, deep in epidermis. produce the pigment melanin which provides protection from ultraviolet light
Langerhans cells
arise from red bone marrow and migrate to the epidermis, special type of white blood cell, release hystamines. participate in immune responses against microbes
Merkel cells
least numerous epidermal cells, located in the deepest layer where they contact the flattened process of a sensory neuron called a tactile (merkel) disc.
Layering of the epidermis
superficial to deep.Stratum corneumStratum lucidum -thick skin onlyStratum granulosumStratum spinosumStratum basale
Thick skin
palms, fingers, soles of feetthick stratum spinosum and corneum, stratum lucidum is present, more dermal papillae (palm, finger,foot prints)
Stratum basale
Deepest layer, stem cells are undergoing mitosis, replace lost skin cells. one row of cuboidal or columnar keratinocytes.
Stratum spinosum
cells bound by desmosomes support for the epidermis, some mitosis is occuring.
Stratum granulosum
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
Stratum lucidum
only in thick skin,, clear layer of dead cells
Stratum corneum
dead cells containing keratin, multiple layers of overlapping cells for protection, gradually lost off surface
2nd deeper part of the skin composed mainly of connective tissue, blood vessels, nerves, glands, and hair follicles.
Papillary layer
1/5 of total dermal layer. areolar connective tissue.
Dermal Papillae
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
Reticular layer
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.
Capillary loops
smooth muscle sphincters regulate blood flow. Normal conserve heat, blushing lose heat.
Color of skin
Melanin, hemoglobin, and carotene 3 pigments that create wide variety of skin colors.
aka pili, offers some protectin from injury and sun (head) decreases heat loss, protects eyes, ears, nose from foreign particles, sensing light touch
hair shaft
superficial portion of the hair which projects above the surface of skin
hair root
portion of hair deep to the shaft that penetrates into the dermis and sometimes into the subcutaneous layer.
3 concentric layers of hair
shaft and root have inner medulla layer, middle cortex, and the cuticle.
hair follicle
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.
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.
hair growth
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.
Sebaceous glands
usually connected to hair follicles, secrete oil onto cuticle of hair. strengthen hair
eccrine sweat glands
sweat on to surface of skin, more common. located in the deep dermis sometimes the upper subcutaneous layer
apocrine sweat glands
sweat onto hair, armpits and groin, begin to function at puberty.
plates of tightly packed, hard, dead, keratinized epidermal cells.
nail matrix
deep to the nail root were cells divide by mitosis to produce growth
nail root
portion that is buried in a fold of skin
aka cuticle a narrow band of epidermis that extends from and adheres to the margin of the nail wall
secures nail to fingertip
nail growth
cells divide by mitosis in the matrix, specialize into nail cells.
superficial wounds
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.
deep wound healing
when a wound extends to the dermis and subcutantious layer. 4 stages.
Inflammatory phase
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.
Migratory phase
scab forms, migration of stratum basale, fibroblasts migrate, blood vessels grow. begins process of healing.
Proliferative phase
epithelial growth, random collagen, blood vessels grow.
Maturation phase
scab sloughs off. organized collagen, normal circulation.
phagocytic white blood cells. come during inflammatory phase
develop into macrophages that phagocytize microbes. come during inflammatory phase
first degree burn
damage to epidermis
second degree burn
damage to dermis
third degree burn
damage to hypodermis and deeper tissues
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