Which of the following blood vessels carries impure blood to the lungs for purification?

Raj. CHO - 2023

Applied Physiology

Easy

Appeared in: Raj. CHO - 2023

Explanation

The question asks to identify the vessel that carries impure (deoxygenated) blood to the lungs.
The pulmonary circulation is responsible for this process.
Blood is pumped from the right ventricle to the lungs via the pulmonary artery.
In the lungs, carbon dioxide is exchanged for oxygen, and the now-oxygenated blood returns to the heart.
Therefore, the pulmonary artery is the vessel that carries deoxygenated blood to the lungs.

Option A: The coronary artery supplies oxygenated blood from the aorta to the heart muscle (myocardium) itself, not to the lungs.
Option B: The portal vein carries deoxygenated, nutrient-rich blood from the gastrointestinal tract and spleen to the liver for processing, not to the lungs.
Option D: The pulmonary vein carries oxygenated (purified) blood from the lungs back to the left atrium of the heart. It carries blood from the lungs, not to them for purification.

Visual 1: Diagram - A clear diagram of the heart showing the four chambers, major vessels, and the pathways of both pulmonary and systemic circulation. Arrows should indicate the direction of blood flow and color-coding (blue for deoxygenated, red for oxygenated) should be used to differentiate the blood types.

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 pulmonary circulation is critical for recognizing conditions like pulmonary embolism (PE). A PE is a blockage in the pulmonary artery, which obstructs blood flow to the lungs, leading to a life-threatening emergency.
A nurse must be able to assess for signs of PE, such as sudden shortness of breath, chest pain, and low oxygen saturation, and escalate care immediately.
What if? If a patient has a large patent foramen ovale (a hole between the atria), a clot from the venous system could cross from the right to the left side of the heart and cause a stroke, bypassing the pulmonary circulation entirely. This is known as a paradoxical embolism.

How to Approach the Question

First, break down the question: it's asking for the vessel that takes 'impure' (deoxygenated) blood 'to the lungs'.
Recall the two main circuits of circulation: systemic and pulmonary.
Remember that the pulmonary circuit's job is to get blood to the lungs to be oxygenated.
Think about the general rule: arteries carry blood away from the heart, and veins carry blood to the heart.
Recall the key exception: The 'pulmonary' artery and vein are exceptions to the oxygenation rule. The pulmonary artery carries deoxygenated blood away from the heart (to the lungs), and the pulmonary vein carries oxygenated blood to the heart (from the lungs).
Evaluate the options based on this knowledge: The pulmonary artery fits the description perfectly.

Concept Tested & Keywords

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