Integumentary System (Functions) Flashcards
hermoregulation
homeostatic regulation of body temperature
the skin liberates sweat at the surface and adjusts flow of blood in the dermis
blood reservoir
ther dermis houses network of blood vessels that carry 8 to 10 % of the totatl blood flow in a resting adult
protection
tightly intelocked cells (keratinocytes) resis invasion by microbes
oily sebrum keeps skin and hair from drying out and kills surface bacteria
keratin
protects the underlying tissue from microbes, abrasions, heat, and chemicals
melanin pigment
helps sheild against damaging effects of UV light
immunological function
aletering immune system to presence of microbial invadersand consuming any that bypass the alerting cells
cutaneous sensations
sensations that arise in the skin: tactile, pain, thermal
tactile sensations
touch, pressure, vibration, and tickling
excretion
elimination of substances from the body
about 400 mL of water evaporates from the corneum daily
sweat
removes heat, salts, carbon dioxide, and byproducts of protein breakdown (ammonia and urea)
absorption
the passage of materials from the external environment into body cells
lipid soluable substances
penetrate the skin including vitamins A,D, E and K, certain drugs, oxygen, and carbon dioxide
synthesis of vitamin D
requeires activation of a precursor molecule in the skin by UV rays in sunlight
enzymes in the liver and kidneys modify the activated molecule
calcitrol
most active form of vitamin D
hormons that aids in the absorption of calcium in foods from the GI tract into the blood
10 to 15 minutes
UV exposure at least twice per week is required fro vitamin D synthesis