QS Study

Regulation of Body Temperature in Cold Climate

Body temperature is the property of the body that determines whether or not the body is in thermal equilibrium with the environment. The anterior hypothalamic-preoptic area contains about one-third cold-sensitive neurons which increase their firing rate when the body temperature falls. This hypothalamus controls normal body temperature through the temperature of the air decreases as low as 55°F. Hypothermia occurs when the core body temperature falls below 35°C. It happens when the body is losing heat faster than it can make it. When we are too cold the blood vessels supplying warm blood to the skin become narrow or constrict (vasoconstriction). This reduces the flow of warm blood near the surface of the skin and reduces heat loss.

Process of Regulation

In cold climate, all mechanisms are played to increase temperature such on.

(A) The decrease in heat loss – By,

Skin vasoconstriction: This is caused by stimulation of the posterior hypothalamic sympathetic renter, which causes low blood flow to gm thus decrease heat loss.

Piloerection: Sympathetic stimulation causes erector pili muscles to contract. Which raises the hair to trap air next to the skin and create a layer of air to act as an insulator.

Inhibit sweating: It decreases the evaporative heat loss.

(B) Increased Heat production by promoting –

  • Shivering,
  • Hunger,
  • Increased voluntary activity,
  • Sympathetic excitation of heat production,
  • Increased secretion of thyroxine,
  • Increased secretion of norepinephrine and epinephrine.