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Not only does this affect supply to the heart muscle itself, but it also can affect the ability of the heart to pump blood throughout the body. Therefore, any disorder or disease of the coronary arteries can have a serious impact on health, possibly leading to angina , a heart attack , and even death.
Interruptions of coronary circulation quickly cause heart attacks (myocardial infarctions), in which the heart muscle is damaged by oxygen starvation. Such interruptions are usually caused by coronary ischemia linked to coronary artery disease , and sometimes to embolism from other causes like obstruction in blood flow through vessels.
Heart development, also known as cardiogenesis, refers to the prenatal development of the heart. This begins with the formation of two endocardial tubes which merge to form the tubular heart, also called the primitive heart tube. The heart is the first functional organ in vertebrate embryos.
This sinus rhythm is important because it ensures that the heart's atria reliably contract before the ventricles, ensuring as optimal stroke volume and cardiac output. [ 4 ] In junctional rhythm, however, the sinoatrial node does not control the heart's rhythm – this can happen in the case of a block in conduction somewhere along the pathway ...
Ventricular escape beats occur when the rate of electrical discharge reaching the ventricles (normally initiated by the heart's sinoatrial node (SA node), transmitted to the atrioventricular node (AV node), and then further transmitted to the ventricles) falls below the base rate determined by the rate of Phase 4 spontaneous depolarisation of ventricular pacemaker cells. [1]
The section shows: 1) the opened ventricles contracting once per heartbeat—that is, once per each cardiac cycle; 2) the (partly obscured) mitral valve of the left heart; 3) the tricuspid and pulmonary valves of the right heart—note these paired valves open and close oppositely. + (The aortic valve of the left heart is located below the ...
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The arroword is a variant of a crossword that does not have as many black squares as a true crossword, but has arrows inside the grid, with clues preceding the arrows. It has been called the most popular word puzzle in many European countries, and is often called the Scandinavian crossword, as it is believed to have originated in Sweden. [30]