thermoregulation

• Thermoregulation is the process of maintaining a constant body temperature.
• 37°c is the optimum body temperature for enzymes to function.
• Thermoregulatory centre helps with thermoregulation, and is inside the hypothalamus.
• The receptor cells detect changes in heat loss/gain from the environment and are mostly in the skin or blood vessels.
• If the body needs to warm up:

  1. Body temp falls due to cold environment
  2. Hypothalamus detects fall and causes body responses
  3. Changes triggered in blood flow so less blood flows near the skin surface (vasoconstriction)
  4. Sweat glands stop producing sweat
  5. Body hairs raised by erector muscles in skin (goosebumps), trapping an insulating layer of air
  6. To generate heat, the body shivers as it requires energy from respiration, and heat energy is released as waste
  7. Reduces transfer of energy to surroundings (less energy is lost)
• If the body needs to cool down:

  1. Body temp rises due to hot environment
  2. Hypothalamus detects rise and causes body response
  3. Changes triggered in blood flow so blood flows near skin surface (vasodilation)
  4. Sweat glands release more sweat onto skin surface to evaporate, sebaceous glands produce oil that helps sweat spread all over skin
  5. Erector muscles relax
  6. Increases energy transfers to surroundings (Lowers body temp)
• Vasoconstriction (when cold):

  • More blood flows through the deep skin blood vessels so less blood flows through surface capillaries

  • This keeps warm blood deeper in the skin so less heat is transferred to the air
• Vasodilation (when hot):

  • Less blood flows through deep skin blood vessels and more blood flows through surface capillaries

  • Increases heat loss by radiation, as heat can transfer easier to the air.