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The heart is a muscular organ situated in the mediastinum.It consists of four chambers, four valves, two main arteries (the coronary arteries), and the conduction system. The left and right sides of the heart have different functions: the right side receives de-oxygenated blood through the superior and inferior venae cavae and pumps blood to the lungs through the pulmonary artery, and the left ...
It may be described as right-left, left-right or bidirectional, or as systemic-to-pulmonary or pulmonary-to-systemic. The direction may be controlled by left and/or right heart pressure, a biological or artificial heart valve or both. The presence of a shunt may also affect left and/or right heart pressure either beneficially or detrimentally.
While in the healthy heart, waves of electrical impulses originate in the sinus node before spreading to the rest of the atria, the atrioventricular node, and finally the ventricles (referred to as a normal sinus rhythm), this normal rhythm can be disrupted. Abnormal heart rhythms or arrhythmias may be asymptomatic or may cause palpitations ...
In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. [1] [2] It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels (from Greek kardia meaning heart, and Latin vascula meaning vessels).
The pericardium (pl.: pericardia), also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. [1] It has two layers, an outer layer made of strong inelastic connective tissue (fibrous pericardium), and an inner layer made of serous membrane (serous pericardium).
Heart failure is caused by chronic oxygen deprivation due to reduced blood flow, which weakens the heart over time. Arrhythmias are caused by inadequate blood supply to the heart that interferes with the heart's electric impulse. The coronary arteries can constrict as a response to various stimuli, mostly chemical. This is known as a coronary ...
The heart muscle may become inflamed in a condition called myocarditis, [46] most commonly caused by a viral infection [47] but sometimes caused by the body's own immune system. [48] Heart muscle can also be damaged by drugs such as alcohol, long standing high blood pressure or hypertension , or persistent abnormal heart racing . [ 49 ]
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