Which of the following contains deoxygenated blood?

Appeared in: JODHPUR AIIMS SNO-2018

Explanation

The pulmonary artery is the correct answer as it is the only artery in the adult human body that carries deoxygenated blood.
It transports this deoxygenated blood from the right ventricle of the heart to the lungs.
In the lungs, the blood releases carbon dioxide and picks up oxygen in a process called gas exchange.
This is a key feature of the pulmonary circulation, which is distinct from the systemic circulation.

Option A: The aorta is the main and largest artery in the body, and it carries oxygenated blood from the left ventricle to be distributed to the entire body through the systemic circulation.
Option C: The subclavian artery is a major branch of the aorta that supplies oxygenated blood to the head, neck, and arms. It is part of the systemic circulation.
Option D: The pulmonary vein is an exception to the general rule for veins. It carries freshly oxygenated blood from the lungs back to the left atrium of the heart.

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 which vessels carry oxygenated versus deoxygenated blood is fundamental for nurses. It is critical for interpreting patient signs and symptoms (like cyanosis, which indicates deoxygenated blood in systemic circulation) and understanding the pathophysiology of cardiopulmonary diseases.
This knowledge is essential when assisting with or interpreting results from procedures like cardiac catheterization, where samples are taken from different heart chambers and vessels to measure oxygen saturation.
What if a newborn presents with central cyanosis (blue lips and tongue)? A nurse should suspect a condition causing right-to-left shunting, where deoxygenated blood from the right side of the heart mixes with systemic circulation, possibly due to a congenital heart defect like Tetralogy of Fallot. The immediate nursing action would be to administer oxygen, monitor vitals, and prepare for further diagnostic tests like an echocardiogram.

How to Approach the Question

First, read the question carefully to identify the key concept: 'deoxygenated blood'.
Recall the general rule of circulation: arteries carry oxygenated blood away from the heart, and veins carry deoxygenated blood toward the heart.
Crucially, remember the two major exceptions to this rule, which occur in the pulmonary circuit.
Evaluate each option based on this knowledge:
Aorta: Main systemic artery, carries oxygenated blood. Incorrect.
Pulmonary artery: Exception to the rule. Carries deoxygenated blood to the lungs. Correct.

Concept Tested & Keywords

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

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 589-591

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