Which blood vessel carries blood from lungs to heart?

AIIMS Rishikesh & Jodhpur NO - 2017

Applied Physiology

Easy

Appeared in: AIIMS Rishikesh & Jodhpur NO - 2017

Explanation

The pulmonary vein is the correct answer as it is the vessel that transports oxygen-rich blood from the lungs to the left atrium of the heart.
This is a critical part of the pulmonary circulation, which is the circuit that runs between the heart and the lungs.
It is a unique exception in the circulatory system, as most veins carry deoxygenated blood, but the pulmonary veins carry oxygenated blood.

Option B: The pulmonary artery carries deoxygenated blood in the opposite direction, from the right ventricle of the heart to the lungs for oxygenation.
Option C: The superior vena cava is part of the systemic circuit. It carries deoxygenated blood from the upper parts of the body (head, neck, arms) to the right atrium of the heart.
Option D: The aorta is the main artery of the systemic circuit. It carries oxygenated blood from the left ventricle of the heart to be distributed to the entire body.

Clinical Relevance

Nursing practice connection: Knowing Pulmonary and Systemic Circulation helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Understanding the direction and oxygenation of blood flow in the pulmonary and systemic circuits is fundamental for nurses. It is essential for cardiopulmonary assessment, interpreting diagnostic tests like echocardiograms, and understanding diseases such as congenital heart defects, heart failure, and pulmonary embolism.
This knowledge is crucial for anticipating the consequences of shunts in the heart. For example, in a patient with an atrial septal defect, deoxygenated blood can mix with oxygenated blood, leading to lower overall oxygen saturation.
What if a patient has transposition of the great arteries (a congenital defect where the aorta and pulmonary artery are switched)? The systemic and pulmonary circuits become parallel, non-communicating loops. Deoxygenated blood from the body returns to the heart and is pumped back to the body, while oxygenated blood from the lungs returns to the heart and is pumped back to the lungs. This is incompatible with life unless there is a shunt (like a VSD or ASD) allowing mixing of blood.

How to Approach the Question

First, break down the question into key components: 'blood vessel', 'from lungs', 'to heart'.
Recall the basic rule of blood flow direction: Arteries carry blood Away from the heart, while Veins carry blood Towards the heart.
Based on the rule, since the blood is flowing 'to heart', the vessel must be a vein. This helps narrow down the options.
Identify the origin of the blood flow, which is the 'lungs'. The term for anything related to the lungs is 'pulmonary'.
Combine these two pieces of information: a vein that comes from the lungs must be the 'pulmonary vein'.
Finally, confirm your answer by recalling the unique nature of the pulmonary circuit, where pulmonary veins carry oxygenated blood, unlike other veins in the body.

Concept Tested & Keywords

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E6 Physiology Essentials Sembulingam 10e Part 2 p. 164-166

E6 Anatomy Applied Ashalatha 4e p. 161-163