Thermoregulation

Thermoregulation is the maintenance of body temperature within a range that enables cells to function efficiently. Mammals, including humans, are endotherms, able to maintain a constant body temperature regardless of our surroundings. The hypothalamus acts as your body’s “thermostat”, detecting changes in body temperature and sending out messages to help restore the normal body temperature.

Response to Heat Stress

• Thermoreceptors (heat) in the skin send messages to the hypothalamus
• AND OR
• Hypothalamus detect a rise in blood temperature
• Hypothalamus sends messages to:
• Signal sent to sweat glands; evaporation of sweat from the skin causes cooling
• Signal sent to blood vessels in the skin, causing them to dilate; more blood flow to the skin and heat lost to skin

Response to Cold Stress

• Thermoreceptors (cold) in the skin send a message to the hypothalamus
• AND OR
• Hypothalamus detects a drop in blood temperature
• Hypothalamus sends messages to:
• Arterioles of the skin causing them to contract; limit blood flow and heat loss
• The smooth muscle around hair follicles of your skin raising the hair; traps warm air near the skin surface
• To skeletal muscles to initiate shivering; rapid muscle contractions generate heat by increasing metabolism