Vakioitermia

Vakioitermia, also known as homeothermy or constant body temperature, refers to the physiological ability of certain animals to maintain a stable internal body temperature regardless of external environmental conditions. This is a characteristic feature of endotherms, which include birds and mammals. Unlike ectotherms, which rely on external sources of heat to regulate their body temperature, homeotherms generate their own internal heat through metabolic processes.

The regulation of body temperature in homeotherms is a complex process controlled by the hypothalamus, a region of the brain. This region acts as a thermostat, sensing changes in blood temperature and initiating physiological responses to either conserve heat or dissipate it. Mechanisms for heat conservation include vasoconstriction (narrowing of blood vessels in the skin) and shivering (involuntary muscle contractions). Heat dissipation can be achieved through vasodilation (widening of blood vessels), sweating, and panting.

Maintaining a constant internal temperature offers several advantages. It allows homeotherms to be active across a wide range of environmental temperatures, providing access to more diverse habitats and food sources. A stable internal temperature also optimizes the functioning of enzymes and metabolic processes, leading to more efficient energy utilization and faster physiological responses. However, homeothermy is energetically expensive, requiring a higher metabolic rate and a greater food intake compared to ectotherms. The evolutionary development of homeothermy has played a significant role in the diversification and success of birds and mammals.