The Heart, Lungs & Circulatory System: How They Work Together

Core Components & Function

The circulatory system efficiently transports oxygen, nutrients, hormones, and waste.

Heart

Four-chambered pump: right side receives deoxygenated blood from body → lungs; left side receives oxygenated blood from lungs → body.

Blood Vessels

• Arteries: Carry oxygen-rich blood away from heart (except pulmonary artery).
• Veins: Return deoxygenated blood to heart (except pulmonary veins).
• Capillaries: Microscopic exchange sites for O₂, CO₂, nutrients, waste.

Blood

Red blood cells (hemoglobin) carry oxygen; plasma transports nutrients, hormones, cells.

Lungs

Alveoli facilitate gas exchange: CO₂ out, O₂ in. Oxygenated blood travels via pulmonary veins to left atrium.

Circulation Loop

1. Body → vena cava → right atrium → right ventricle → pulmonary artery → lungs.
2. Lungs → pulmonary veins → left atrium → left ventricle → aorta → body.

This continuous flow sustains cellular respiration and homeostasis.