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Structure of the Human Heart[edit]
The human heart is a muscular organ responsible for pumping blood through the circulatory system. It is located in the thoracic cavity, between the lungs, and is roughly the size of a fist. The heart is composed of four chambers: two upper chambers called the atria and two lower chambers called the ventricles.
Chambers of the Heart[edit]
The heart's four chambers are crucial for its function:
- Right Atrium: Receives deoxygenated blood from the body through the superior vena cava and inferior vena cava.
- Right Ventricle: Pumps deoxygenated blood to the lungs via the pulmonary artery.
- Left Atrium: Receives oxygenated blood from the lungs through the pulmonary veins.
- Left Ventricle: Pumps oxygenated blood to the rest of the body through the aorta.
Valves of the Heart[edit]
The heart contains four main valves that ensure unidirectional blood flow:
- Tricuspid Valve: Located between the right atrium and right ventricle.
- Pulmonary Valve: Located between the right ventricle and the pulmonary artery.
- Mitral Valve: Located between the left atrium and left ventricle.
- Aortic Valve: Located between the left ventricle and the aorta.
Heart Wall[edit]
The heart wall consists of three layers:
- Epicardium: The outer layer, which is also part of the pericardium.
- Myocardium: The thick, muscular middle layer responsible for the heart's contractile function.
- Endocardium: The inner layer that lines the heart chambers and valves.
Conduction System[edit]
The heart's electrical conduction system controls the heartbeat:
- Sinoatrial Node (SA Node): The natural pacemaker of the heart, located in the right atrium.
- Atrioventricular Node (AV Node): Relays electrical impulses from the atria to the ventricles.
- Bundle of His: Transmits impulses from the AV node to the ventricles.
- Purkinje Fibers: Distribute the electrical impulse throughout the ventricles.
Function[edit]
The primary function of the heart is to maintain blood circulation throughout the body. It achieves this by:
- Pumping deoxygenated blood to the lungs for oxygenation.
- Pumping oxygenated blood to the tissues and organs.
Related pages[edit]
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