Blood flow in pulmonary veins is-

RUHS, Jaipur, PB B.Sc Nursing Entrance-2023

Applied Physiology

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2023

Explanation

The pulmonary circulation is the part of the circulatory system that carries deoxygenated blood from the right ventricle to the lungs, and returns oxygenated blood from the lungs to the left atrium.
The pulmonary veins are the specific blood vessels responsible for the final step of this circuit.
They collect oxygen-rich blood from the alveolar capillaries in the lungs after gas exchange has occurred.
This oxygenated blood is then transported directly to the left atrium, which acts as the receiving chamber before the blood is passed to the left ventricle for systemic circulation.

Option B: This describes the reverse of the correct flow. Blood does not flow from the left atrium back to the lungs in a healthy circulatory system. Blood flows from the left atrium to the left ventricle.
Option C: This is incorrect because blood from the lungs must first enter the left atrium before it can be passed into the left ventricle. The mitral valve separates the left atrium and left ventricle.
Option D: This describes the function of the pulmonary artery in reverse and from the wrong ventricle. The left ventricle pumps oxygenated blood into the aorta for systemic circulation, not to the lungs. It is the right ventricle that pumps blood to the lungs.

Clinical Relevance

Nursing practice connection: Knowing Pulmonary Circulation helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Understanding the direction of blood flow is fundamental for assessing cardiac function and diagnosing congenital heart defects or acquired heart diseases.
Anomalies like Total or Partial Anomalous Pulmonary Venous Return (TAPVR/PAPVR) are serious congenital defects where the pulmonary veins drain into the right atrium or other systemic veins instead of the left atrium, leading to mixing of oxygenated and deoxygenated blood.
What if? If a patient has pulmonary vein stenosis (narrowing of the pulmonary veins), the flow of oxygenated blood from the lungs to the left atrium would be obstructed. This would increase pressure in the lungs (pulmonary hypertension) and reduce the amount of oxygenated blood available to the body, leading to symptoms like shortness of breath and fatigue.

How to Approach the Question

This is a factual recall question about cardiovascular anatomy and physiology.
First, identify the key structure in the question: 'pulmonary veins'.
Recall the two main circulatory loops: systemic and pulmonary.
Remember that the right side of the heart handles deoxygenated blood going to the lungs, and the left side handles oxygenated blood coming from the lungs and going to the body.
Visualize the path of blood: Lungs -> Pulmonary Veins -> Left Atrium -> Left Ventricle -> Aorta -> Body -> Vena Cava -> Right Atrium -> Right Ventricle -> Pulmonary Artery -> Lungs.
Based on this path, determine that pulmonary veins carry blood from the lungs to the left atrium and select the matching option.

Concept Tested & Keywords

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E6 Physiology Essentials Sembulingam 10e Part 2 p. 165-167