Heartbeat and Pulse | Physiology | Biology | FuseSchool

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Heartbeat and Pulse | Physiology | Biology | FuseSchool

Ever wonder what causes the thump-thump sound of your heartbeat?

It’s all to do with the valves. The sound of your heart beating can be attributed to your valves closing, and always in specific pairs.

Separating the atria from the ventricles are the tricuspid and bicuspid valves.The pulmonary valve and the aortic valve ensure that deoxygenated and oxygenated blood, respectively, leave the heart entirely without any backflow. This beautiful system sees that both the tricuspid and bicuspid valve are closed when the ventricles, both left and right, contract – this contraction forces blood out of the heart, through the pulmonary arteries and aorta.

The first thump that you can feel is the sound of the tricuspid and bicuspid valves closing simultaneously.

So during systole (the first half of your heartbeat) the tricuspid and bicuspid valves are closed, but the pulmonary and aortic valves are open. Once the ventricles relax, the pulmonary and aortic valves close, causing the second thump of a heartbeat. When the pulmonary and aortic valves are closed, the tricuspid and bicuspid valves automatically open.

During diastole, blood (both oxygenated and deoxygenated) fills into the heart.

The average heart rate for a young adult varies, depending on age, physical size, genetics, and activity. It is usually in the range of 60 – 100 heartbeats per minute. The fitter you are, the lower your resting heart rate is likely to be. An athlete may have a resting heart rate closer to 40 beats a minute.

After each heartbeat, a pressure wave passes along your arteries, which causes your arterial walls to bulge, and then contract. These pulses, as they are called, can be felt at various points throughout your body. A strong pulse can be felt at the top of your neck.

Although you cannot quantitatively measure the force of your pulse, you can do so for the overall force exerted against arterial walls by your blood – this is called blood pressure.

Usually your blood pressure is given as two numbers. These numbers represent the forces exerted during systole and diastole, known as systolic pressure and diastolic pressure. The systolic pressure is quoted before the diastolic.

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