13/04/2026
Human Heart – Full Definition
The heart is a muscular organ that works as a pump to circulate blood throughout the body. It supplies oxygen and nutrients to tissues and removes carbon dioxide and waste products.
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Main Parts of the Heart
1. Chambers (4 parts)
• Right Atrium: Receives deoxygenated (impure) blood from the body through the superior vena cava and inferior vena cava.
• Right Ventricle: Pumps this blood to the lungs through the pulmonary artery.
• Left Atrium: Receives oxygenated (pure) blood from the lungs through the pulmonary veins.
• Left Ventricle: Pumps oxygen-rich blood to the whole body through the aorta.
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2. Valves (control blood flow)
• Tricuspid Valve: Between right atrium and right ventricle
• Pulmonary Valve: Between right ventricle and pulmonary artery
• Mitral (Bicuspid) Valve: Between left atrium and left ventricle
• Aortic Valve: Between left ventricle and aorta
👉 These valves ensure blood flows in one direction only.
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3. Major Blood Vessels
• Superior Vena Cava: Brings blood from upper body to heart
• Inferior Vena Cava: Brings blood from lower body
• Pulmonary Artery: Carries blood from heart to lungs
• Pulmonary Vein: Carries oxygenated blood from lungs to heart
• Aorta: Largest artery; carries blood from heart to entire body
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Working of the Heart (Blood Flow)
1. Body → Right atrium (via vena cava)
2. Right atrium → Right ventricle
3. Right ventricle → Lungs (via pulmonary artery)
4. Lungs → Left atrium (via pulmonary vein)
5. Left atrium → Left ventricle
6. Left ventricle → Whole body (via aorta)
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Short Summary
The heart continuously pumps blood in a cycle:
• Right side → sends blood to lungs
• Left side → sends oxygenated blood to body