Trace pulmonary vessels between heart and lungs
Identify the outgoing and returning vessels in a complete lung circuit.
Core and Extended; Biology 0610, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked
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
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.
Pause and explain
Which vessel returns blood from lungs to heart?
Worked example
Complete right ventricle → X → lungs → Y → left atrium and describe the change at lungs.
Show the worked solution
- X carries blood away from the heart: pulmonary artery.
- 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.
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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.
Name the vessel from the right ventricle to the lungs.
Give me a hint
It is the outgoing lung route.
Compare my reasoning
- The destination is lungs.
- The away-from-heart direction defines an artery.
Pulmonary artery.
Look for these in your work
- Use destination
- Use direction
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
- Right ventricle supplies pulmonary artery and lungs.
- 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
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
- a. means artery and v. means vein.
- 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.
What can you explain now?
Which vessel returns blood from lungs to heart?
Compare with the explanation
Pulmonary vein
It enters the left atrium.
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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.