Right ventricle
Left pulmonary artery
Superior lobar artery
Pulmonary trunk
Right pulmonary artery
Middle lobar artery
Interior lobar artery
Left ventricle
The Correct Answer and Explanation is :
Correct Labeling of the Anatomical Features of Pulmonary Circulation (in sequence of blood flow):
- Right Ventricle
- Pulmonary Trunk
- Right Pulmonary Artery and Left Pulmonary Artery
- Superior Lobar Artery
- Middle Lobar Artery (right lung only)
- Inferior Lobar Artery
- Left Ventricle (not part of pulmonary circulation directly)
Explanation (Approx. 300 words):
Pulmonary circulation refers to the part of the cardiovascular system responsible for transporting deoxygenated blood from the heart to the lungs and returning oxygenated blood back to the heart. It plays a vital role in gas exchange—removing carbon dioxide and absorbing oxygen.
The journey begins in the right ventricle, which pumps deoxygenated blood into the pulmonary trunk, the main artery leaving the right side of the heart. The pulmonary trunk then bifurcates (splits) into the right and left pulmonary arteries, which transport blood to the corresponding lungs.
Within each lung, these pulmonary arteries branch further into lobar arteries—named according to the lobes of the lung they supply:
- The right lung has three lobes (superior, middle, and inferior), and therefore it has:
- Superior lobar artery
- Middle lobar artery
- Inferior lobar artery
- The left lung has two lobes (superior and inferior), so it lacks a middle lobar artery but includes:
- Superior lobar artery
- Inferior lobar artery
Each lobar artery continues branching into segmental arteries that further supply the lung tissue for gas exchange.
After oxygenation in the alveoli, oxygen-rich blood returns to the left atrium via the pulmonary veins. From there, it passes into the left ventricle, which is not a direct part of pulmonary circulation but rather systemic circulation. The left ventricle then pumps oxygenated blood throughout the body.
To summarize:
- Pulmonary circulation is a low-pressure system transporting blood from the right ventricle through the pulmonary arteries into the lungs and returning it via pulmonary veins to the left atrium.
- Lobar arteries distribute blood to lung regions, enabling gas exchange essential for survival.