Homéothermie

Homéothermie refers to the ability of warm-blooded animals to maintain a stable internal body temperature regardless of the surrounding environment. This physiological process is crucial for survival and optimal functioning of metabolic processes. Organisms that exhibit homéothermie are known as homeotherms or endotherms. They generate their own heat through metabolic activity, a process called thermogenesis. This internal heat production allows them to thrive in a wide range of temperatures, from very cold to very hot climates.

To regulate their body temperature, homeotherms employ various physiological mechanisms. These include shivering, which increases heat production through muscle activity, and sweating or panting, which promote heat loss through evaporation. Blood flow can also be manipulated; vasoconstriction reduces blood flow to the skin, conserving heat in cold conditions, while vasodilation increases blood flow, aiding heat dissipation when it's warm. Behavioral adaptations also play a role, such as seeking shade or basking in the sun.

The primary regulatory center for body temperature in mammals is the hypothalamus, a region of the brain. It acts as a thermostat, receiving information about body temperature from sensors throughout the body and initiating appropriate responses to maintain the set point. Birds and mammals are the most well-known examples of homeotherms. This ability to maintain a constant internal temperature has allowed them to occupy diverse ecological niches and achieve high levels of activity and sustained performance compared to cold-blooded animals, or poikilotherms, whose body temperature fluctuates with their surroundings.