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What happens in you in a Heartbeat?



Today we'll study something interesting. We want to peep into our hearts and see what really happens each time we feel our hearts beating. It is called the CARDIAC OR HEART CYCLE.

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The Cardiac Cycle.

Describes all the activities of the heart through one complete heartbeat; that is through one contraction and relaxation of the ventricles and atria.

Phases of the Cardiac Cycle.
The cardiac cycle is majorly divided into two known as the systole and diastole.

The Diastole is the phase where the atria and ventricles are in a relaxed mode.
- During this phase blood is pumped into both straight from the large veins of systemic circulation; ( superior and inferior Vena Cava) and the pulmonary veins.

- Blood fills the ventricles passively as both the mitral and tricuspid valves that are at located between the ventricles and atria are lifted.

- The left atrium receives oxygenated blood from the pulmonary veins while the right receives deoxygenated from the superior and inferior vena cava.

- At the end stage of the diastolic phase the atria begin to contract and propel additional blood into the respective ventricles.


The Systole.
This phase refers to the period during which the ventricles contract and eject blood into the aorta for circulation and pulmonary arteries for oxygenation respectively.

- This phase begins with the closure of the valves between the atria and ventricles and that closure is what is responsible for the first heart sound you hear.

The heart beats in a 'lub-dub' fashion, the 'lub' being the first heart sound and the second which is happens as a result of the closure of the aortic and pulmonary valves following the pumping of blood.

All these activities take place in just a heartbeat.
So each time you feel your heart beat. Just remember that is what happens during those split seconds.

Credits:
Science direct.com
The physiologist.org
Cliff notes.com
Lumenlearning.com
cvphysiology.com




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