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Biology

GCSE · Edexcel

QuestionsFlashcards

Photosynthesis
Plant Structure
Transport in Plants
Plant Hormones
- Plant Hormones & Growth
  7
- Using Plant Hormones Commercially
  7

Transport in Animals
- The Need for Transport
  7
- Factors Affecting the Rate of Diffusion
  7
Respiration
- Respiration
  6
- Practical: Investigating Respiration
  5
Gas Exchange
Circulatory System
- The Blood & Blood Vessels
  6
- The Circulatory System
  8

Vasoconstriction & Vasodilation Flashcards

All 6 cards in this deck

What is vasodilation and what effect does it have?: Blood vessels near the skin surface widen, so more blood flows near the surface and more thermal energy is lost — it cools the body down.
What is vasoconstriction and what effect does it have?: Blood vessels near the skin surface narrow, so less blood flows near the surface and less thermal energy is lost — it keeps the body warm.
True or false? During vasodilation the blood vessels move closer to the skin surface.: False. Blood vessels cannot move; they widen so that more blood flows through the vessels near the surface.
True or false? Vasoconstriction happens when the body is too hot.: False. Vasoconstriction happens when the body is too cold, to reduce heat loss.
What effect does shivering have on body temperature, and why?: It raises it — muscles contract and relax rapidly, increasing respiration, which releases thermal energy.
Iguanas have no sweat glands and pant with their mouths open when too hot. What cools them down?: Water evaporates from the mouth, removing latent heat (thermal energy) so their temperature falls.