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Why the heart and blood vessels are needed

Why the heart and blood vessels are needed

Annotated mammalian heart showing four chambers, valves, major vessels and arrows for double circulation

Large mammals cannot rely on diffusion alone because they have a small surface area to volume ratio and many cells lie far from the external environment. They need mass transport, the bulk movement of substances in a transport medium such as blood.

Heart, blood vessels and cardiac cycle Lesson

  1. A Level
  2. /Biology
  3. /Heart, blood vessels and cardiac cycle

Step-by-step lessons covering Edexcel A A Level Biology Heart, blood vessels and cardiac cycle for A Level Biology. Each lesson works through exam-style questions in Paper 1, Paper 2 and Paper 3 format. Build a strong foundation in cell biology and biochemistry early on, since later topics on genetics, ecology and physiology all draw on these core concepts.

Lessons