The pulmonary circulation involves movement of the blood to and from the

Step 1: Analyze the question The question asks which organs the blood travels to and from in the pulmonary circulation.

Step 2: Explain the concept The word "pulmonary" comes from the Latin pulmo, meaning lung. Anything labeled "pulmonary" relates to the lungs. For example, the pulmonary artery, pulmonary vein and pulmonary circulation all involve the lungs.

Mammals, including humans, have a double circulation:

• Pulmonary circulation: heart ↔ lungs
• Systemic circulation: heart ↔ the rest of the body (brain, kidney, liver, etc.)

Step 3: Trace the pathway

1. Deoxygenated blood leaves the right ventricle.
2. It travels through the pulmonary artery to the lungs.
3. In the lungs, the blood gives up carbon dioxide and picks up oxygen.
4. Oxygenated blood returns through the pulmonary veins to the left atrium.

Step 4: Check the options

• A. Brain: supplied by the systemic circulation (carotid arteries). ✗
• B. Kidney: supplied by the systemic circulation (renal artery). ✗
• C. Liver: supplied by the systemic circulation (hepatic artery and hepatic portal vein). ✗
• D. Lungs: the destination and source in pulmonary circulation. ✓

Memory tip: Pulmonary = Lungs. The pulmonary artery is the only artery that carries deoxygenated blood, and the pulmonary vein is the only vein that carries oxygenated blood. WASSCE often tests this exception, so remember it.