Functions Flashcards
What are the functions of the integumentary system
Protection, sensation, excretion, vitamin D synthesis
Describe protection
-protects from mechanical trauma, pathogens and environment
Stratified squamous keratinized epithelium gives durable, flexible surface; protects body from mechanical trauma (stretching, pressure, abrasions)
-barrier to invasion by microorganisms and pathogens
-has cells of immune system that destroy pathogens before they invade deeper tissues
-glands secrete antimicrobial substances, protection from environmental hazards
What does sensation do
-perceives changes in body
-receptors detect potentially harmful stimuli (heat, cold, pain) that could lead to tissue damage
What happens when body temperature rises above normal range
-Sensory receptors (thermoreceptors) detect increase in temp. in skin and internal body fluids
-control center in hypothalamus acts as thermostat (thermoregulatory center), receives input from thermoreceptors and responds to inputs
-control center stimulates sweating, sweat glands are stimulated to release sweat
What happens when body temperature rises above normal range (continued)
-control center stimulates cutaneous vasodilation, dermal blood vessels widen (dilate), increased blood flow through vessels increases heat radiated from body
-body temp. returns to normal range and cooling mechanisms decline by negative feedback; no more signals to hypothalamus, control center responses end, sweating and vasodilation ends
What happens body temperature drops below normal range (due to cold environmental conditions)
-thermoreceptors detect body temp. below range; relay info to thermoregulatory center in hypothalamus
-blood vessels in dermis narrow (vasoconstrict), reducing blood flow; heat lost to environment is limited
What happens when body temperature drops below normal range (continued)
-vasoconstriction redirects blood flow to deeper tissue; conserves heat
-hypothalamus stops signaling, heat conservation ends, feedback loop is closed after body temp. returns to normal
What does excretion
Eliminates waste products and toxins; occurs in kidneys
How does skin create vitamin D
-Modified cholesterol is converted to cholecalciferol by exposure to epidermis to UV radiation
-cholecalciferol released into blood; first modified by liver, then kidneys, forming calcitriol (active form of vitamin D)
-Calcium ion: for nerve function, muscle contraction, building and maintaining bone tissue
