Blood Flow: Does It Always Go to the Lungs First? Corrected Circulation Pathway

The statement that blood must go to the lungs before entering the heart is inaccurate. The heart is the first organ blood enters after leaving the lungs.

Corrected Circulatory Pathway

Pulmonary Circulation

1. Deoxygenated blood from body → right atrium.
2. Right atrium → right ventricle.
3. Right ventricle → pulmonary arteries → lungs.
4. In lungs: CO₂ released, O₂ picked up → oxygenated blood.

Systemic Circulation

1. Oxygenated blood from lungs → pulmonary veins → left atrium.
2. Left atrium → left ventricle.
3. Left ventricle → aorta → body.
4. Aorta branches → smaller arteries → tissues/organs.

The heart receives deoxygenated blood via the vena cava, pumps it to the lungs for oxygenation, then pumps oxygenated blood to the body. Pulmonary and systemic circulations are separate circuits.