Thermoception

In physiology, thermoception or thermoreception is the sensation and perception of temperature, or more accurately, temperature differences inferred from heat flux. It deals with a series of events and processes required for an organism to receive a temperature stimulus, convert it to a molecular signal, and recognize and characterize the signal in order to trigger an appropriate response. Thermal stimuli may be noxious (posing a threat to the subject) or innocuous (no threat). The temperature sensitive proteins in thermoreceptors may also be activated by menthol or capsaicin, hence why these molecules evoke cooling and burning sensations, respectively.

A thermoreceptor may absorb heat via conduction, convection or radiation. However, the type of heat transfer is usually irrelevant to the functioning of a thermoceptor. Transient receptor potential channels (TRP channels) are believed to play a role in many species in sensation of hot, cold, and pain. Vertebrates have at least two types of thermoreceptors: those that detect heat and those that detect cold.

Heat transfer

Thermoception depends on the transfer of heat from the environment to the thermoreceptor. The transfer may be conductive, convective or radiative, but the method is irrelevant to the thermoceptor, which simply detects its own temperature, not that of the environment.