theme 30 temp met 3 Flashcards
what is countercurrent exchange of heat?
transfer of thermal energy from warm arterial blood to cooler venous blood (in endotherms)
what things use countercurrent blood flow?
birds and some mammals
why do marine birds use countercurrent blood flow in their legs?
to minimize heat loss
what do poikilotherms have in place of a thermoneutral zone?
preferred temp
incipient upper lethal temperature
incipient lower lethal temperature
what does incipient lethal temperature mean?
temperature at which 50% of animals die
how is preferred temperature measured?
on a thermal gradient
what does acclimation temperature change?
tolerance range
preferred temp
what is changed in tissues because of acclimation?
mitochondrial density and muscle enzymes
what two strategies do poikilotherms do during freezing?
freeze tolerance
extracellular fluids freeze
freeze avoidance by antifreeze molecules
that depress freezing point
What does the countercurrent exchange of heat depend on? the close or distant anatomical relationship between arteries and veins?
the close relationship to make sure the limb doesnt freeze when saving heat
Does the arterial or venous side of countercurrent exchange of heat vasodilate and constrict?
the arterial can do both but venous cant
do ectotherms or endotherms use counter-current exchange of heat to supply the limbs and muscles with heat?
ectotherms supply limbs with heat, and endotherms decrease the heat in the limbs
true or false: endotherms and ectotherms use counter-current exchange of heat for the same reason.
false, they use it for opposite reasons
what are the two types of thermal acclimation strategies that ectotherms have?
quantitative: increase number of mitochondria (more quantity)
qualitative: alter the type of metabolic machinery (alter to get quality)
what is thermal acclimation?
when ectotherms remodel tissues in response to long-term changes in temperature
