https://wikimd.org/index.php?action=history&feed=atom&title=Cardiac_cycleCardiac cycle - Revision history2026-05-13T07:24:56ZRevision history for this page on the wikiMediaWiki 1.44.2https://wikimd.org/index.php?title=Cardiac_cycle&diff=4962170&oldid=prevPrab at 13:36, 18 May 20232023-05-18T13:36:00Z<p></p>
<p><b>New page</b></p><div>The '''cardiac cycle''' refers to the sequence of events that occurs when the [[heart]] beats. It consists of two main phases: the diastole phase and the systole phase.<ref name="cardiac_cycle">{{cite web|url=https://www.ncbi.nlm.nih.gov/books/NBK279250/|title=Cardiac Cycle|publisher=NCBI Bookshelf|accessdate=2023-05-03}}</ref> During the cardiac cycle, the heart chambers contract and relax to pump blood to the [[pulmonary circulation|lungs]] and the [[systemic circulation|rest of the body]].<br />
[[File:Cardiac-Cycle-Animated.gif|thumb|Cardiac-Cycle-Animated]]<br />
=== Diastole Phase ===<br />
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''Main article: [[Diastole]]''<br />
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During the '''diastole phase''', the heart ventricles are relaxed and the heart fills with blood. This phase consists of three stages: early diastole, when the atria and ventricles are both relaxed; atrial systole, when the atria contract to push blood into the ventricles; and late diastole, when the atria relax again.<ref name="diastole">{{cite web|url=https://www.ncbi.nlm.nih.gov/books/NBK279250/|title=Cardiac Cycle|publisher=NCBI Bookshelf|accessdate=2023-05-03}}</ref><br />
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=== Systole Phase ===<br />
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''Main article: [[Systole]]''<br />
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During the '''systole phase''', the ventricles contract, pumping blood out of the heart. This phase has two stages: isovolumetric contraction, when the ventricles first begin to contract with all valves closed, and ventricular ejection, when the ventricles continue to contract, pushing blood out of the heart.<ref name="systole">{{cite web|url=https://www.ncbi.nlm.nih.gov/books/NBK279250/|title=Cardiac Cycle|publisher=NCBI Bookshelf|accessdate=2023-05-03}}</ref><br />
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== Regulation of the Cardiac Cycle ==<br />
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The cardiac cycle is regulated by the [[sinoatrial node]] (SA node), often referred to as the heart's natural pacemaker. The SA node sends out electrical signals that travel through the heart, causing it to contract and pump blood.<ref name="sa_node">{{cite web|url=https://www.nhlbi.nih.gov/health-topics/how-heart-works|title=How the Heart Works|publisher=National Heart, Lung, and Blood Institute|accessdate=2023-05-03}}</ref><br />
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== Clinical Significance ==<br />
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Understanding the cardiac cycle is crucial in the field of cardiology. Disruptions in the cardiac cycle can lead to various heart conditions, including [[arrhythmia|arrhythmias]], [[heart failure]], and [[ischemic heart disease]].<ref name="clinical_significance">{{cite web|url=https://www.ncbi.nlm.nih.gov/books/NBK279250/|title=Cardiac Cycle|publisher=NCBI Bookshelf|accessdate=2023-05-03}}</ref><br />
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==Related Pages==<br />
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* [[Heart]]<br />
* [[Diastole]]<br />
* [[Systole]]<br />
* [[Electrical conduction system of the heart]]<br />
== References ==<br />
{{reflist}}<br />
[[Category:Cardiology]]<br />
[[Category:Cardiovascular physiology]]<br />
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