lesson
Blood passes through two connected circuits
1 · Learn
The human circulatory system has a pulmonary circuit between heart and lungs and a systemic circuit between heart and the rest of the body. Valves help maintain one-way flow. Arteries carry blood away from the heart and veins towards it.
Those vessel names describe direction, not always oxygen content. The pulmonary artery carries blood with relatively low oxygen towards the lungs.
2 · Worked example
The left side pumps oxygenated blood to the body; the right side pumps blood to the lungs. Separate paths help maintain suitable pressures.
3 · Your turn
Why is 'all arteries carry oxygenated blood' incorrect?
Check your answer
The pulmonary artery carries relatively deoxygenated blood away from the heart to the lungs.
4 · Apply your learning
Trace a labelled model route without mixing the pulmonary and systemic circuits.
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Check a calculation · Year 5 onward
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Powers, roots and trigonometry · Year 7 onward
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