The correct option is Right ventricle → pulmonary artery → lungs → left atrium.
Explanation
The human circulatory system is a double circulation system comprising two distinct loops: pulmonary circulation and systemic circulation. Pulmonary circulation is the pathway responsible for transporting deoxygenated blood from the heart to the lungs for oxygenation and returning oxygenated blood back to the heart.
Detailed Analysis
The flow of blood in pulmonary circulation follows this specific sequence:
- Right Ventricle: Deoxygenated blood is pumped from the right ventricle into the pulmonary trunk.
- Pulmonary Artery: The pulmonary trunk splits into pulmonary arteries, which carry deoxygenated blood to the lungs. This is a unique exception where arteries carry deoxygenated blood.
- Lungs: Gas exchange occurs in the pulmonary capillaries; carbon dioxide is unloaded, and oxygen is picked up.
- Left Atrium: Oxygenated blood returns to the heart through the pulmonary veins, entering the left atrium.
Thus, the correct pathway is Right ventricle → Pulmonary artery → Lungs → Left atrium.
Contrast with Systemic Circulation: Left ventricle → aorta → tissues → right atrium represents systemic circulation, where oxygenated blood flows from the Left Ventricle → Aorta → Tissues → Right Atrium.
Key Takeaway: Pulmonary circulation connects the heart and lungs, starting at the right ventricle (deoxygenated) and ending at the left atrium (oxygenated).