Alternative conceptions in physics are ideas held by people regardless of their age, ability, sex, race and religion. The persistence and universality of these misconceptions suggest that there must be a common underlying factor found in all human beings. In this work, we suggest how the structure and arrangement of our thermosensory system shapes and constrains the creation of the concepts of heat and temperature. Firstly, we outline the main characteristics of alternative conceptions in physics. Then, we describe the neurobiology of thermosensation. The proteins sensitive to temperature changes can be classified as hot- and cold-sensitive. The nervous system maintains mostly this separation in hot- and cold-fibres and thermal information is integrated in specific areas of the central nervous system. Therefore, it seems that the neurobiological structure predisposes us to categorise stimuli into hot and cold. Understanding the relationship between alternative conceptions and the structure of the nervous system can improve the abilities of teachers to deal with students’ ideas. In particular, this knowledge could decrease the frustration of teachers, since they would understand that human physiology is a determinant factor. Therefore, they should not expect to easily modify their students’ alternative conceptions.