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IGCSE · Cambridge (CIE) · 0654

Trace pulmonary vessels between heart and lungs

Identify the outgoing and returning vessels in a complete lung circuit.

Blood vessels · Cambridge IGCSE 0654 · B9.3

Mapped to the named 0654 section using teaching from the corresponding single-science course. A 0654-specific review of every Core and Supplement objective is still in progress. Written practice is self-checked; it does not demonstrate supervised laboratory competence or award an official Cambridge grade.

Before you begin

  • Recall arteries, veins and gas exchange.

Work on paper. Try each question before revealing help, and explain why your method works.

Quick readiness check

What does pulmonary refer to?

What you will learn

  • Pulmonary is a destination clue
  • Direction and gas exchange are separate ideas
Follow right ventricle → pulmonary artery → lung exchange → pulmonary vein → left atrium. Diagram colours are conventions, not definitions.The lung circuitRight ventriclePulmonary arteryLung capillary networkPulmonary veinLeft atrium
Follow right ventricle → pulmonary artery → lung exchange → pulmonary vein → left atrium. Diagram colours are conventions, not definitions. Original schematic, not to scale.

Pulmonary is a destination clue

Pulmonary means associated with the lungs. The pulmonary artery connects the right ventricle with the lung capillary network. After gas exchange, the pulmonary vein connects that network with the left atrium. Identify both vessels, not just the outgoing one, when asked for the lung blood supply.

The original vertical route is right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium. These vessels belong to a circuit joined to the systemic circuit; it is not an isolated stock of blood that never returns to the rest of the body.

Direction and gas exchange are separate ideas

In this normal adult model, blood arriving at lungs in the pulmonary artery has relatively less oxygen. At the exchange surface it gains oxygen and loses carbon dioxide. It then returns in the pulmonary vein with relatively more oxygen. Blood is not oxygenated by the artery name or the vein name.

A label covering “pulmonary artery and vein” on a whole-body image names a pair. Resolve which is which by tracing away from or towards the heart, then check the gas-exchange sequence. Colour alone is not a robust definition, particularly for pulmonary vessels.

Sources for this lesson

Pause and explain

Which vessel returns blood from lungs to heart?

Put the idea to work

Worked example

Complete right ventricle → X → lungs → Y → left atrium and describe the change at lungs.

Show the worked solution
  1. X carries blood away from the heart: pulmonary artery.
  2. Y returns it: pulmonary vein; lung exchange increases oxygen content.

Answer X pulmonary artery; Y pulmonary vein. Oxygen enters blood at lungs and carbon dioxide leaves it.

Try a topic test

Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.

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From guided practice to a new situation

Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.

1 · Guided

Name the vessel from the right ventricle to the lungs.

Give me a hint

It is the outgoing lung route.

Compare my reasoning
  1. The destination is lungs.
  2. The away-from-heart direction defines an artery.

Pulmonary artery.

Look for these in your work

  • Use destination
  • Use direction
2 · Independent

Write the complete lung route between the two named heart chambers.

Give me a hint

Insert both pulmonary vessels around the exchange region.

Compare my reasoning
  1. Right ventricle supplies pulmonary artery and lungs.
  2. Pulmonary vein returns to left atrium.

Right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium.

Look for these in your work

  • Include both vessels
  • Keep chamber connections correct
3 · Transfer

A combined image label says “pulmonary a. and v.”. Why are both identity and direction needed?

Give me a hint

Expand the abbreviations and follow each branch.

Compare my reasoning
  1. a. means artery and v. means vein.
  2. One route goes to lungs and the other returns; they differ in oxygen content after exchange.

Identify pulmonary artery away from the heart and pulmonary vein towards it; the paired label alone does not replace tracing the two routes.

Look for these in your work

  • Expand the label
  • Separate both directions

Common mistakes

  • Sending lung-return blood directly to the right ventricle.
  • Calling a pulmonary artery an oxygenated vessel by definition.
Recall without your notes

What can you explain now?

Which vessel returns blood from lungs to heart?

Compare with the explanation

Pulmonary vein

It enters the left atrium.

After trying it yourself, choose your next review. This is your self-assessment.

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Make it stick

Name both lung vessels and locate their heart chambers.

If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.

Keep learning Sciences — Co-ordinated (Double)

Course scope and assessment

This 2028–2029 pathway maps all 152 detailed subject-content sections in the published 0654 syllabus to original teaching and staged practice. It adapts teaching from the related single-science pathways and excludes clear 0610-only topics such as classification systems, human excretion, tropic responses, food supply, population dynamics, detailed pollution and biotechnology. Some explanations may include wider single-science context. A 0654-specific objective-by-objective review, Core/Supplement audit, human subject-teacher review, supervised laboratory experience and cumulative assessment remain in progress. Written practice is self-checked and does not predict an official grade. The 2025–2027 syllabus has not been reconciled here; choose the 2028–2029 syllabus only.

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