The Heart's Four Chambers: Anatomy and Blood Flow Explained

Chamber-by-Chamber Blood Flow

1. Right Atrium

Receives deoxygenated systemic venous blood via the superior vena cava (upper body) and inferior vena cava (lower body).

2. Right Ventricle

Contracts → pumps blood through the pulmonary valve into the pulmonary artery → lungs for oxygenation.

3. Left Atrium

Receives oxygenated blood from the lungs via four pulmonary veins.

4. Left Ventricle

Contracts → pumps blood through the aortic valve into the aorta → systemic circulation.

Cardiac Cycle Coordination

• Atrial systole: Both atria contract simultaneously → fill ventricles.
• Ventricular systole: Both ventricles contract simultaneously → pulmonary and systemic ejection.
• Valves (tricuspid, pulmonary, mitral, aortic) ensure unidirectional flow, opening/closing passively via pressure gradients.

Clinical Relevance

Chamber enlargement, valve dysfunction, or conduction abnormalities disrupt this sequence, causing heart failure, arrhythmias, or hypoxia.