Final answer:
The auditory canal's main role is in hearing, by guiding sound waves toward the tympanic membrane; it is not involved in ear temperature regulation. Variations in the canal's length affect resonance and the ear's sensitivity to frequencies, which is considered in medical diagnostics like ear thermometers.
Step-by-step explanation:
The auditory canal is part of the human ear's structure that is responsible for directing sound waves toward the tympanic membrane. While its primary function relates to hearing, it is not directly involved in temperature regulation of the ear itself. However, the ear can play a role in thermoregulation more broadly, as certain medical devices, like the infrared ear thermometer developed using NASA technology, measure body temperature via the eardrum due to the amount of energy it emits. The auditory canal's length, which can vary from 1.80 to 2.60 cm in the average population, affects its ability to resonate at certain frequencies. Understanding this resonance frequency and its relationship to the human ear's sensitivity to various frequencies is essential for designing hearing-related applications and medical diagnostics.