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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 ...
The size of the heart varies among the different animal groups, with hearts in vertebrates ranging from those of the smallest mice (12 mg) to the blue whale (600 kg). [142] In vertebrates, the heart lies in the middle of the ventral part of the body, surrounded by a pericardium. [143] which in some fish may be connected to the peritoneum. [144]
Coronary vessel branches that remain on the surface of the heart and follow the sulci of the heart are called epicardial coronary arteries. [1] The left coronary artery distributes blood to the left side of the heart, the left atrium and ventricle, and the interventricular septum.
Heart disease is a type of cardiovascular disease that affects the heart’s structure and function. Several different heart conditions fall under the umbrella term for heart disease.
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).
This is the strongest part of the fibrous cardiac skeleton. The upper chambers ( atria ) and lower ( ventricles ) are electrically divided by the properties of collagen proteins within the rings. The valve rings, central body, and skeleton of the heart consisting of collagen are impermeable to electrical propagation.
The coronary arteries are the arterial blood vessels of coronary circulation, which transport oxygenated blood to the heart muscle. The heart requires a continuous supply of oxygen to function and survive, much like any other tissue or organ of the body. [1] The coronary arteries wrap around the entire heart.
Cardiac cells have two refractory periods, the first from the beginning of phase 0 until part way through phase 3; this is known as the absolute refractory period during which it is impossible for the cell to produce another action potential. This is immediately followed, until the end of phase 3, by a relative refractory period, during which a ...