Patho Exam 2 Flashcards
(328 cards)
largest organ of the body
skin
functions of the skin
temperature control/regulation barrier protection secretion/absorption vitamin D production immunological surveillance indicative of disease process, overall health
how to increase absorption rate @ skin?
put medication of skin, occlude (cover). will increase rate of absorption, effects.
approximately what percentage of PCP visits are related to skin conditions?
50%
why are skin disorders more likely with age?
amount of elastin/collagen decreases (can’t heal as well), skin thins and gets weaker, immune system decreases so cannot fight off conditions as well (skin cancer) or mount inflammatory response as well, cumulative effects of environmental exposure (sun, chemicals, topical agents over time)
____% of Americans have a skin condition; ____% of older adults have some form of skin disorder
30%; 90%
epidermis
aka stratum germinativum
outermost layer of skin
few cells thick
stratum germnivatum
two layers: basal and squamous
contains column-shaped basal cells, move upward towards skin and flatten, die, shed
stratum granulosum
contains more keratinocytes moving upward toward surface
stratum lucidum
only on palms of hands, soles of feet
stratum coreum
outermost layer of epidermis
made of dead, flat, keratinocytes that shed every 2 weeks
whole layer shed every 3-4 weeks
dead cells contain large amt of keratin (insoluble fibrous protein that form barrier of skin)
keratin
insoluble fibrous protein that forms barrier of skin
principle hardening protein of hair, nails
has the ability repel pathogens and prevent excessive fluid loss
three specialized cells @ epidermis
melanocytes (produce pigment) Langerhans cells (1st line immune defense) Merkel cells (mechanoreceptors, transmit stimuli, involved in f'n of touch)
largest portion of skin
dermis
dermis
largest portion of skin
provides strength, structure
includes connective tissue, blood capillaries, oil/sweat glands, nerve endings, hair follicles
hypodermis (subcutaneous tissue)
innermost layer of skin primarily adipose tissue thickness varies by person vital for body temp regulation provides cushioning between skin/muscle/bone
how does skin control/regulate temp?
skin has temp sensors, send info to hypothalamus
brain sends signals to skin’s sweat glands and blood vessels
Cooling: glands excrete sweat to cool down body (evaporation)
Heating: erector muscles contract, raise hair on skin to trap air, provide insulation, and keep body warm
80% of heat loss occurs via the…?
skin
how does the skin provide barrier protection to body?
- -natural barrier, keratinized cells
- -skin has bacteria, thick lipid film (sweat, sebaceous secretions) that repels virulent bacteria/ prevents infection
- -surface film, thick surface layer (stratum corneum) prevent antigens from entering body & keep it waterproof
how skin is involved in excretion
By influencing the composition and volume of sweat, the skin influences total fluid volume and quantity of excreted waste products
minor compared to renal, respiratory excretion
what waste products are excreted @skin?
water, heat, salt, carbon dioxide, ammonia, and urea
what is absorbed @ skin?
- -fat-soluble substances (Vit ADEK)
- -O2, CO2, organic solvents, CCl4, heavy metal salts, poison ivy/oak oils
- -fat soluble medications (skin permeable to them)
how is skin involved in the production of Vit D?
1st step in vit D synthesis is @ skin: 7-dehydrocholesterol converted to cholecalciferol (precursor to vit D)
–then, synthesis @ liver, kidney
what does vitamin D do?
- -regulates Ca2+ and P (phosphorous) metabolism
- -facilitates calcium absorption from the intestine
- -affects bone cell development