Which sequence correctly describes the pathway of blood flow through the heart?

Which sequence correctly describes the pathway of blood flow through the heart?

• A. Right atrium — Tricuspid valve — Right ventricle — Pulmonic valve — Pulmonary artery — Lungs — Pulmonary veins — Left atrium — Bicuspid (Mitral) valve — Left ventricle — Aortic valve — Aorta
• B. Right atrium — Tricuspid valve — Right ventricle — Aortic valve — Aorta — Systemic circulation — Pulmonary veins — Left atrium — Mitral valve — Left ventricle — Pulmonary artery — Lungs
• C. Right atrium — Mitral valve — Left atrium — Tricuspid valve — Right ventricle — Pulmonary artery — Lungs — Pulmonary veins — Left ventricle — Aorta
• D. Right atrium — Pulmonic valve — Right ventricle — Tricuspid valve — Left atrium — Mitral valve — Left ventricle — Aortic valve — Aorta — Systemic circulation

Answer: (A)

The heart’s flow starts with deoxygenated blood returning to the right atrium, then flowing through the tricuspid valve into the right ventricle. From there it passes through the pulmonic valve into the pulmonary artery and goes to the lungs for gas exchange. After picking up oxygen, blood returns via the pulmonary veins to the left atrium, moves through the mitral valve into the left ventricle, and is then ejected through the aortic valve into the aorta to supply the body. This sequence correctly routes blood from the right heart to the lungs and back to the left heart before systemic distribution, with each valve ensuring one-way flow. The other sequences misplace valves, skip the lungs, or mix up chamber-to-chamber transitions, which would disrupt the proper circulation.