Edexcel GCSE Biology
The heart, blood and circulation — Edexcel GCSE Biology revision
Free revision notes, key terms, common exam traps and 5 practice questions with answers. About 5 minutes to read.
Double circulation
- Right side pumps deoxygenated blood to the lungs; left side pumps oxygenated blood around the body.
- The left ventricle wall is thicker because it pushes blood much further.
- Blood flows: vena cava → right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta.
Blood vessels and blood
- Arteries: thick muscular elastic walls, high pressure, carry blood away from the heart.
- Veins: thin walls, wide lumen, valves to stop backflow.
- Capillaries: one cell thick for fast diffusion.
- Blood = plasma, red blood cells (haemoglobin, no nucleus), white blood cells, platelets.
Key terms
- Double circulation
- Blood passes through the heart twice per full circuit.
- Haemoglobin
- Protein in red blood cells that binds oxygen.
- Coronary artery
- Supplies the heart muscle itself with blood.
- Stent
- A tube that holds a narrowed artery open.
- Double circulatory system
- Blood passes through the heart twice per full circuit — once to the lungs, once around the body.
- Artery
- A vessel carrying blood away from the heart, usually oxygenated, with thick muscular walls.
Common exam traps
- Mixing up 'artery = oxygenated' — the pulmonary artery carries deoxygenated blood.
- Saying red blood cells have a nucleus. They lose it to fit in more haemoglobin.
- Labelling the heart diagram from your own left instead of the patient's.
Practice questions with answers
1. Which vessel carries deoxygenated blood away from the heart?
- • Aorta
- • Pulmonary artery
- • Pulmonary vein
- • Vena cava
Answer: Pulmonary artery
It takes blood from the right ventricle to the lungs.
2. Explain why the left ventricle has a thicker muscular wall than the right.
Answer: It generates a higher pressure to pump blood all around the body, not just to the nearby lungs.
Link thickness → pressure → distance.
3. Capillary walls are one cell thick. Why does this help?
- • It increases blood pressure
- • It shortens the diffusion distance
- • It stores oxygen
- • It prevents clotting
Answer: It shortens the diffusion distance
Substances exchange quickly with the tissue.
4. Give one advantage and one disadvantage of a stent.
Answer: Advantage: keeps the artery open and restores blood flow for years. Disadvantage: risk of infection or a clot forming.
Balanced answers score both marks.
5. Why is the left ventricle wall thicker than the right ventricle?
- • It pumps blood only to the lungs
- • It pumps blood around the whole body, needing more force
- • It's not actually thicker
- • It contains more valves
Answer: It pumps blood around the whole body, needing more force
Blood needs higher pressure to travel around the whole body compared to the short trip to the lungs.
Keep going in the app
This topic has 55 questions in total, plus flashcards, cram mode and Grade 9 Push challenges.
More free Biology revision
- All Edexcel Biology revision pages
- All GCSE Biology topics
- Edexcel Biology: Cell structure and organelles
- Edexcel Biology: Transport in and out of cells
- Edexcel Biology: Cell division and stem cells
- Edexcel Biology: Enzymes and digestion
- Edexcel Biology: Pathogens and communicable disease
- Edexcel Biology: Photosynthesis
- Every subject on ReviseRush
ReviseRush is an independent educational revision aid. It is not affiliated with, endorsed by or connected to AQA, Edexcel, OCR, WJEC, Pearson or any exam board. All notes and questions are original. Always check content against your official course and specification. No grade outcome is guaranteed.