Control of temperature

2.6.2 Control of water & ion content

2.6.4 Control of blood glucose

Control of temperature

  1. Body temperature is monitored & controlled by the thermoregulatory centre in the brain1, which has receptors sensitive to the temperature of the blood flowing through it
  2. Temperature receptors in the skin sends information about skin temperature to the thermoregulatory centre
  3. Sweating helps cool the body but more water is lost when it is hot so more fluid must be taken through drink or food to balance this

  4. High temperature

    1. Blood vessels supplying skin capillaries dilate so that more blood flows through the capillaries and more heat is lost2
    2. Sweat glands release more sweat, which cools the body as it evaporates
    3. Hairs on the skin lie flat, preventing heat from being trapped by a layer of still air between the hairs

  5. Low temperature

    1. Sweat production decreases
    2. Blood vessels supplying skin capillaries constrict so that less blood flows through them3
    3. Hairs on the skin stand on end, trapping a layer of insulating air
    4. Muscles may “shiver”, and their contraction requires respiration, which produces some heat to warm the body
    5. Mitochondria can convert fat directly into heat energy
  1. This is called the hypothalamus ↩
  2. This is called arteriolar vasodilation ↩
  3. This is called arteriolar vasoconstriction ↩