Thermoregulation

• The regulation of temperature in the body is detected by thermoreceptors
• Thermoreceptors pass the information on to the hypothalamus
• Based on the input from thermoreceptors, the hypothalamus initiates appropriate responses to either increase or decrease body temperature
• Cooling Mechanisms

  • Sweating- the hypothalamus activates sweat glands through nerve fibres
  • Vasodilation - the hypothalamus causes blood vessels in the skin to dilate (expand), increasing blood flow to the skin. This allows more heat to be lost  to the environment through radiation, convection and conduction
• Heating Mechanisms 

  • Shivering - the hypothalamus triggers involuntary muscle contractions (shivering) to generate heat through increase metabolic activity 
  • Vasoconstriction - the hypothalamus causes blood vessels in the skin to constrict (narrow), reducing blood flow to the skin minimising heat loss 
  • Non-shivering Thermogenesis - in response to cold, the hypothalamus stimulates the release of hormones like norepinephrine that increase metabolic activity in brown adipose tissue, producing heat without muscle contractions