Thermoregulationssystem

Thermoregulation is the physiological process by which animals maintain internal body temperature within a narrow optimal range despite environmental temperature changes. It ensures stable enzymatic function and metabolism, supporting activity, growth, and survival.

In mammals, the hypothalamus serves as the central regulator. Thermoreceptors in the skin, spinal cord, and core transmit temperature information, which the hypothalamus compares with a set point. Negative feedback elicits autonomic and behavioral responses to correct deviations.

Effector responses include vasodilation and vasoconstriction of skin vessels, sweating or shivering, and adjustments in metabolic heat production. When hot, the body increases heat loss through radiation, convection, and evaporation; when cold, it reduces heat loss and increases heat generation.

Endotherms generate most of their heat metabolically, while ectotherms rely more on environmental heat and behavioral strategies. Several species use brown adipose tissue for non-shivering thermogenesis, particularly in infants and small mammals; adults generally rely on shivering and metabolic adjustments.

Clinical aspects include fever, a regulated rise in the set point during infection, and pathological states such as hypothermia and hyperthermia. Aging, obesity, and certain neurological conditions can impair thermoregulation.

Thermoregulation has significant evolutionary and ecological implications, contributing to the distribution of species and their activity patterns. It is studied in physiology, medicine, and ecology to understand responses to heat stress, cold exposure, and climate change.