UNIT 2.4 Flashcards
a conformer
an organism in which its external environment impacts its internal environment - internal fluctuates
- low metabolic costs because they do not have the energy demand that comes with regulating own temperature (physiological homeostasis)
- restricted ecological niches (narrow)
a regulator
an organism in which its external environment does not effect internal environment (constant internal conditions)
- wide range of ecological niches
- high metabolic cost
thermoregulation
maintaining a constant internal body temperature
the principal thermoregulation by negative feedback control
- hypothalamus detects changes in the body temperature (temp reg centre)
- messages sent along nerves as electrical impulses to effectors
effectors bring about the corrective response returning temp to normal
correction of overheating
vasodilation
arteries leading to the skin become dilated, allows for large volumes of blood to flow through capillaries near skin surface
correction of overheating
increased rate of sweating
heat energy from body is used to convert the water in sweat to water vapour - heat loss by evaporation
correction of overheating
relaxation of arrestor pili muscles
hairs lie flat and therefore there is no layer of trapped warm air insulating the body
correction of overheating
decreased metabolic rate
less hear is produced
correction of overcooling
vasoconstriction
blood vessels become restricted = less blood flow to skin = less heat is lost
correction of overcooling
contraction of arrector pili muscles
hairs being raised from skins surface, traps a lay of warm insulating air
correction of overcooling
shivering
muscle contraction generates heat
correction of overcooling
increased metabolic rate
more heat produced
correction of overcooling
sweating
water = cools
