AQA Biology 4.5.2.4

Thermoregulation

Your core stays close to 37 °C on a hot run or a cold swim. Push the body too hot or too cold and watch the skin respond.

Triple Science · Higher tier

Start here

Red in the face.

You finish a sprint race on a warm afternoon, and a friend says your face has gone bright red.

If you had to guess, is your body trying to lose heat, or keep it?

Control

The thermoregulatory centre.

Body temperature is monitored and controlled by the thermoregulatory centre in the brain (the hypothalamus). Enzymes work best near 37 °C: above about 40 °C they start to denature, and below about 35 °C is hypothermia. Tap each part of the system.

The general receptor, coordination centre and effector pattern: Homeostasis.

Responses

Too hot, too cold.

Push the body off 37 °C and watch the skin.

At 37 °C: no correction needed.

Triple Higher

Explain it in context

Explain how each mechanism lowers or raises body temperature in the situation you are given. Pick one.

Pick a situation.

Why shivering releases energy: respiration, in Aerobic respiration.

Think again · moving vessels?

“When you’re hot, your blood vessels move closer to the skin.”

Your call

Choose

What happens to the blood vessels supplying the skin when you are too hot?

Sort

Too hot or too cold?

Place each response.

Tap a card, then tap the box it belongs in. Tap a placed card to take it back.

Command words in this lesson

Describe: The responses when the body is too hot or too cold.
Explain: How a response lowers or raises body temperature, in a given context (Triple Higher).
Name: Where body temperature is monitored.

Key fact

Too hot: blood vessels dilate and sweat is produced; both transfer energy from the skin to the environment. Too cold: vessels constrict, sweating stops, muscles shiver.

Key note · AQA 4.5.2.4 (Triple)

Thermoregulation

The thermoregulatory centre in the brain monitors and controls body temperature; its receptors detect blood temperature, and skin receptors send impulses to it.
Too hot: vasodilation and sweating. Both transfer energy from the skin to the environment.
Too cold: vasoconstriction, sweating stops, skeletal muscles shiver.
Explain in context: blood flow changes energy transfer; evaporation transfers energy; shivering needs respiration, which releases energy.

Photograph this card. Tomorrow, cover it and say each line first.

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Connects to

Ask MrBadmus

Mixing up vasodilation and vasoconstriction?

The skin diagram is schematic and not to scale.