Thermoregulation in Endotherms

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Detecting Temperature Changes:

  • Receptors are needed to detect a change in the internal environment, peripheral temperature receptors are in the skin and detect surface temperature changes
  • Temperature receptors in the hypothalamus detect the temperature of the blood deep in the body
  • Temperature of the skin is more likely to be affected by external environments
  • Combination of the two means maintenance of body temperature with 1 degree of 37 degrees is important 

Principles of Thermoregulation:

  • Use internal exothermic metabolic activities to maintain warmth and energy-requiring physiological responses to cool them down 
  • Behavioural Responses:
    • Basking in the Sun or pressing body against warm surfaces
    • Wallowing in water or mud to cool down and digging burrows
    • Some go into hibernation to avoid heat stress or cold weather
    • Humans wear clothes and houses are built to alter how cold or hot it is
  • Physiological Adaptations:
    • Peripheral temperature receptors
    • Thermoregulatory centres in hypothalamus
    • The skin and the muscles

Cooling Down:

  • Vasodilation: Arterioles near surface of the skin dilate and the shunt vessels constrict, forces blood through the capillary network to the surface of the skin and the skin flushes and cools from radiation. If pressed against cool surface it cools due to conduction
  • Increased Sweating: Sweat spreads across surface of the skin and as…

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