Thermoregulation Flashcards
Endotherm definition
use internally generated heat to maintain body temperature
Ectotherm definition
depend on external heat sources, body temperature changes with environment
Homeotherm definition
maintain constant internal body temperature
Poikilotherm definition
varies its internal body temperature within range of temperature
Thermoneutral zone definition
range of ambient temperatures where body can maintain core temperature solely through regulating dry heat loss
Lower & upper critical temperatures definition
limit of thermoneutral zone, at this point animal actively works to maintain core body temperature
Zone of thermal comfort definition
temperature range within which animals comfort is optimal
Thermal set point definition
temperature which all body systems attempt to return core temperature to
Where is thermoregulation regulated
Thermoregulatory centre in hypothalamus
Contains receptors sensitive to temperature of blood (thermoreceptors)
Send nerve impulses to effectors in skin & muscles to maintain body temperature
How do endotherms respond to cold
Shivering
Vasoconstriction
Contraction of hair follicles
Reduced metabolic activities
Reduced sweating
Decreased blood flow in skin capillaries
How do endotherms respond to heat
Sweating
Vasodilation
Increased blood flow in skin capillaries
Name some special adaptations of homeotherms
Fat layer/blubber (cold)
Fur/wool (cold)
Panting (hot)
Elephants radiate heat from ears (hot)
Shedding (hot)
Hibernation (cold)
How does conduction result in heat loss
Occurs when animal’s body comes into direct contact with cooler surface
Heat flows from warm body to cooler surface
How does convection result in heat loss
Occurs when fluid flows over animal’s body, carrying heat away
How does radiation result in heat loss
Occurs when animal’s body emits infrared radiation which is absorbed by cooler surfaces in environment
