Coronary Arteries – Definition and Function

Definition of Coronary Arteries Coronary Arteries are the network of arteries that encircles the heart to provide its blood supply. The two primary coronary arteries, the right coronary artery and the left coronary artery, branch from the aorta as it arises from the left ventricle. The left coronary artery is significantly larger and supplies the left heart. It […]

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Endocardium – Definition and Function

Definition of Endocardium and Function Endocardium is the membrane that lines the inner heart, made up of epithelial cells. It also covers the heart valves, providing a smooth surface that offers no opportunity for blood cells (particularly platelets) to stick to it as they pass through the heart. The endocardium contains Purkinje fibers, specialized muscle cells that convey the electrical impulses that […]

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Heart Rate – Definition and Information

Definition of Heart Rate and Information Heart Rate is the number of times in a minute that the heart completes a cardiac cycle, commonly measured as the pulse. At rest, the healthy adult heart beats between 60 and 80 times per minute. The heart rate of a person who is aerobically fit is slower because the […]

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Heart – Health, Disease and Definition

Definition of Heart Heart is the organ that pumps blood and maintains circulation. About the size of a closed fist, the heart resides in the chest between the lungs, slightly offset to the left behind the protective sternum (breastbone). It begins beating at about 3 weeks gestational age and during a typical life time contracts about 2.5 billion […]

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Myocardium (Muscle Tissue Heart) – Definition and Function

Definition of Myocardium The muscle tissue that forms the walls of the heart. Myocardial cells are unique in their structure, blending muscle and nerve structures so they can both contract and conduct electrical impulses. Myocardial cells thus can contract independent of external stimulation. The myocardial fibers of the atria have a different configuration from those […]

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Pericardium – Definition, Function and Types

Definition of Pericardium and Function A tough, two-layer membranous sac that encloses the heart. Is vulnerable to inflammation and infection (pericarditis). The pericardium’s fibrous outer layer, called the fibrous pericardium, protects the heart from contact with the chest wall and other structures in the chest, including the lungs and the sternum. The pericardium wraps completely around the heart, extending around the bases of […]

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Pulmonary Arteries – Function and Definition

Definition of and Function Pulmonary Arteries – The large blood vessels that carry blood from the heart to the lungs. The main artery arises from the right ventricle and immediately branches into the right and left arteries. The pulmonary arteries are the only arteries in the body that transport deoxygenated blood. Like other arteries, however, the pulmonary arteries have sturdy, muscular walls […]

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The Cardiovascular System – Function and Disease

Cardiovascular System Definition The cardiovascular system circulates blood through the body to deliver nutrients and collect wastes from cells. Physician specialists who treat conditions of the heart and blood vessels are cardiologists. Functions of the Cardiovascular System The cardiovascular system circulates blood through the body to supply cells with nutrients, notably oxygen and glucose, and to remove the waste […]

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Pulmonary Veins – Function and Definition

Definition of Pulmonary Veins The large blood vessels that bring blood to the left side of the heart from the lungs. The main pulmonary veins arise from the lungs and branch immediately into the right pulmonary vein and the left pulmonary vein. The right pulmonary vein carries blood from the right lung and the left pulmonary […]

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Artery – Definition and Function

Definition of Artery and Function Artery is a flexible, muscular blood vessel that carries blood from the heart and oxygenated blood to tissues throughout the body. The wall of an artery has three layers: adventitia, the outermost layer, which is primarily connective tissue that gives the artery its flexibility media, the middle layer, which is mostly smooth muscle tissue that gives […]

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