Temperature control

• All: Why is it important to maintain your body temperature.

• Most: How your body stops you from getting too hot/cold.

• Some: How other animas reduce heat loss.

Keeping comfortable

The Inuit people live on

the Arctic coasts, for

example parts of

Greenland, Siberia,

and Alaska.

Average temperatures in the far north of Alaska range

from –30 °C in winter to 2 °C in summer. Further south

the temperature range is –12 °C to 15 °C.

The Tuareg live mainly in West Africa, for example Mali.

The average temperature in Mali ranges from 25 °Cin winter to 35 °C.

Why control temperature?

Too low - reactions become too slow for cells to survive

Too high - body’s enzymes are at risk of denaturing.

The body must be kept at a constant temperature of 37 °C. Why?

Optimum temperature for the body’s enzymes. Even slight changes in body temp can have a life-threatening effect on health.

Why control temperature?

How is temperature controlled?Body temperature is monitored and controlled by temperature receptors in the skin and brain (thermoregulatory centre)

Thermoregulatory centreThese receptors detect changes in the temperature of blood flowing through those areas.

If body temperature deviates from 37

°C, these receptors send out electrical signals to the thermoregulatory centre that trigger actions that increase or decrease heat loss.

How is temperature controlled?

1. Control of temperature relies on receptors. Where are temperature receptors located?

2. What do these temperature receptors do?

3. Why does skin appear red when we are hot?

4. Why do we drink more in hot weather?

Keeping warm/coolHow can heat be gained?

How can heat be lost?

shivering

vasoconstriction

wearing extra clothing.

sweating

vasodilation

removing extra clothing.