Body temperature is regulated by balancing heat production and heat loss. The normal human body temperature ranges from 97-99°F orally and 36.1-37.2°C rectally. Temperature is precisely controlled through neural, vascular, behavioral and other physiological mechanisms. Fever is defined as a temperature above the normal range due to infection, illness or other causes, while hypothermia is a temperature below 35°C due to cold exposure or other factors. Nursing care focuses on monitoring temperature, providing supportive care and rewarming or cooling interventions as needed to maintain a normal temperature range.