De-oxygenated blood is transported to the lungs through the

Step 1: Analyze the question The question asks which vessel carries de-oxygenated blood (blood low in oxygen, high in carbon dioxide) to the lungs.

Step 2: Explain the concept Remember the general rule:

• Arteries carry blood away from the heart.
• Veins carry blood toward the heart.

The pulmonary circulation is the exception to the "arteries carry oxygenated blood" idea:

• Pulmonary artery: carries de-oxygenated blood from the right ventricle to the lungs.
• Pulmonary vein: carries oxygenated blood from the lungs to the left atrium.

Step 3: Follow the blood's path

1. De-oxygenated blood from the body enters the right atrium (via the vena cava).
2. It passes to the right ventricle.
3. The right ventricle pumps it through the pulmonary artery to the lungs.
4. In the lungs, carbon dioxide is released and oxygen is picked up.
5. Oxygenated blood returns through the pulmonary vein to the left atrium.

Step 4: Check each option

• A. Renal vein: carries blood from the kidneys, not to the lungs. Wrong.
• B. Hepatic portal vein: carries nutrient-rich blood from the intestines to the liver. Wrong.
• C. Pulmonary artery: carries de-oxygenated blood from the heart to the lungs. Correct.
• D. Pulmonary vein: carries oxygenated blood from the lungs to the heart. Wrong.

Answer: C. Pulmonary artery

Exam tip: Think "A for Away." Arteries carry blood away from the heart, so the pulmonary artery takes blood away from the heart to the lungs. The pulmonary artery and pulmonary vein are the only pair where the artery carries de-oxygenated blood and the vein carries oxygenated blood. JAMB loves testing this exception, so remember it.