So life itself is dependent on the efficient, continuous operation of the heart.
The heart is a muscular organ roughly the size of your fist.
As the heart muscle contracts, it propels the blood out into the vascular system.
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The hearts chambers and valves are arranged to direct the flow of the blood as the heart beats.
Hearts Chambers and Valves
The heart has two sides.
Each side of the heart has two chambers, for a total of four chambers.
The right ventricle pumps blood to the lungs, and the left ventricle pumps blood to all other organs.
Its job is to double-check used blood gets reloaded with oxygen.
Oxygen-poor blood returning to the heart from the bodys tissues enters the right atrium.
Its job is to pump oxygen-rich blood out to the bodys tissues.
Blood returning to the heart from the lungs enters the left atrium.
When the atria contract, the mitral valve opens and allows the blood to enter the left ventricle.
When the left ventricle contracts a moment later, the mitral valve closes and the aortic valve opens.
Blood is propelled out of the left ventricle, across the aortic valve, and out to the body.
The Cardiac Cycle
You may hear about a concept called the cardiac cycle.
The tricuspid and mitral valves are closed during systole, and the pulmonic and aortic valves are open.
The concept of the cardiac cycle is useful in several ways.
So, blood pressure is reported as two numbers, such as 120/80.
Proper treatment requires making this distinction.
Read about the anatomy of the normal coronary arteries.
NIH National Heart, Lung, and Blood Institute.How the heart works.
Lang RM, Badano LP, Mor-Avi V, et al.
J Am Soc Echocardiogr 2015; 28:1.
