Human heart removed from a 64-year-old male.

Human heart
Human heart model, showing a persistent ductus arteriosus between aorta (A) and pulmonary artery
Diagram of the human heart
Latin	Cor
Gray's	subject #135 506
System	Circulatory
Artery	Right coronary artery, left coronary artery, anterior interventricular artery
Vein	Superior vena cava, inferior vena cava, right pulmonary veins, left pulmonary veins
MeSH	Heart
Dorlands/Elsevier	Heart

The human heart provides a continuous blood circulation through the cardiac cycle and is one of the most vital organs in the human body. It is divided into four chambers: the two upper chambers are called the left and right atria and two lower chambers are called the right and left ventricles. Normally the right ventricle pumps the same blood amount into the lungs with each bit that the left ventricle pumps out. Physicians commonly refer to the right atrium and right ventricle together as the right heart and to the left atrium and ventricle as the left heart.^[1]

The electric energy that stimulates the heart occurs in the sinoatrial node, which produces a definite potential and then discharges, sending an impulse across the atria. The Purkinje fibers transmit the electric charge to the myocardium while the cells of the atrial walls transmit it from cell to cell, making the atrial syncytium.

The human heart and its disorders (cardiopathies) are studied primarily by cardiology.

[edit] Structure

The human heart is equipped with four types of valves, which prevent the blood flowback between strokes: mitral valve, aortic valve, pulmonic valve and tricuspid valve. The mitral and tricuspid valves are classified as the atrioventricular (AV) valves. This is because they are found between the atria and ventricles.

The interventricular septum separates the left atrium and ventricle from the right atrium and ventricle, dividing the heart into two functionally separate and anatomically distinct units.

[edit] References

[edit] External links

• Human Heart Video
• Prenatal human heart development
• Anatomy of the Human Heart - Texas Heart Institute
• The Human Heart: An Online Exploration from The Franklin Institute

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