The human heart is a muscular organ responsible for pumping blood throughout the body via the circulatory system. It plays a vital role in delivering oxygen and nutrients to tissues and removing carbon dioxide and other wastes.
Structure
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The heart is divided into four chambers:
- Right atrium
- Right ventricle
- Left atrium
- Left Ventricle
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The left side handles oxygenated blood from the lungs to the body.
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The right side handles deoxygenated blood from the body to the lungs.
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Key valves ensure one-way blood flow:
- Tricuspid valve (right side)
- Pulmonary valve
- Mitral valve (left side)
- Aortic valve
Blood Flow Pathway
- Body → right atrium → right ventricle → lungs
- Lungs → left atrium → left ventricle → body
(See also: Circulatory System)
Conduction System
- The heart has its own electrical system that controls heartbeat:
- SA Node (sinoatrial node) – natural pacemaker
- AV Node (atrioventricular node)
- Bundle of His
- Purkinje fibers
(See: Cardiac Cycle)
Key Concepts
- Cardiac output = heart rate × stroke volume
- Pulse = a measure of heartbeats per minute
- Blood pressure = force of blood against artery walls