Thermoregulation - Blood Vessels
Biology: AQA GCSE Higher, topic 5.2.19
Thermoregulation - Blood Vessels
Blood vessels deep in the skin have layers of smooth muscle tissue in their walls. They respond differently when we are too hot or too cold.
Too hot
- If we are too hot, then the muscular walls relax.
- This is called vasodilation.
- This allows more blood to enter and flow through capillaries close to the skin surface. The excess heat energy is transferred to the surroundings.
Too cold
- If we are too cold, then the muscular walls contract.
- This is called vasoconstriction.
- This reduces the blood flow to the skin surface and heat energy is kept inside the body.
Test yourself on Thermoregulation - Blood Vessels
Which of the following are true of vasodilation?
How does blood flow near the skin differ between vasodilation and vasoconstriction?
Why does more heat energy leave the body during vasodilation?
Why do ducks decrease the blood flow to their feet in cold water?
Why is the blood flowing to a duck's feet cooled before it arrives?