thermal balance

Thermal balance

Condition where heat production equals heat loss

Thermal balance equation

HP = qr + qc + qd + qe

HP

metabolic heat production

qr

radiant heat transfer

qc

convective heat transfer

qd

conductive heat transfer

qe

evaporative heat loss

Heat production greater than heat loss

Body temperature increases

Heat production less than heat loss

Body temperature decreases

Thermal neutral zone

Temperature range where animals maintain body temperature with minimal metabolic heat production

Factors affecting TNZ

Acclimation, humidity, air movement, age, weight, sunlight

Upper critical temperature

Temperature above which animals must increase evaporative heat loss

Lower critical temperature

Temperature below which animals must increase metabolic heat production

Pilomotion

Fluffing fur to increase insulation

Ptilomotion

Fluffing feathers to increase insulation

Shivering thermogenesis

Heat produced through muscle contractions

Non-shivering thermogenesis

Heat produced metabolically without muscle movement.

Sensible heat

Heat transfer involving a temperature change without phase change

Sensible heat examples

Conduction, convection, radiation

Latent heat

Heat transfer involving a phase change

Evaporative heat loss

Heat lost when water evaporates

Latent heat examples

Sweating, panting, respiratory evaporation