Which of the following correctly lists the sequence of blood flow through the heart starting from the vena cava?

• A. Vena cava → left atrium → left ventricle → pulmonary artery → lungs → pulmonary vein → right atrium → right ventricle → aorta
• B. Vena cava → right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta
• C. Aorta → left ventricle → left atrium → pulmonary vein → lungs → pulmonary artery → right ventricle → right atrium → vena cava
• D. Pulmonary vein → right atrium → right ventricle → aorta → lungs → left atrium → left ventricle → vena cava

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the basic anatomy of the heart and the direction of blood flow. Blood flows through the heart in a specific sequence, starting from the vena cava, which brings deoxygenated blood from the body to the heart.
2. Step 2: Identify the chambers of the heart and their roles. The heart has four chambers: the right atrium, right ventricle, left atrium, and left ventricle. Deoxygenated blood enters the right atrium first.
3. Step 3: Trace the path of deoxygenated blood. From the right atrium, blood flows into the right ventricle, which pumps it into the pulmonary artery. The pulmonary artery carries the blood to the lungs for oxygenation.
4. Step 4: Trace the path of oxygenated blood. After oxygenation in the lungs, blood returns to the heart via the pulmonary vein, entering the left atrium. From the left atrium, blood flows into the left ventricle, which pumps it into the aorta to be distributed throughout the body.
5. Step 5: Compare the given sequences to the correct path of blood flow. The correct sequence is: Vena cava → right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta.