preview

The Phases from One Heartbeat to the Next Essay

Satisfactory Essays
The cardiac events that take place from the beginning of the heart beat to the beginning of the next one are called as the Cardiac Cycle. There are three main phases in the cycle that we will discuss below:
1. Ventricular filling: Mid-to-late Diastole:
During the diastole phase, the atria and ventricles are relaxed and therefore the atrioventricular valves are open, the ventricles are the primary pumps of the heart, therefor the term diastole typically refers to the relaxation of the ventricles. Now when the heart is in the state of relaxation and the pressure within the heart is low, this is when the blood is passively flowing through the atria and in to the ventricles. De oxygenated blood from the superior and inferior vena cava
…show more content…
Therefore rights after ventricular systole occurs the pressure is passed along and start rising in these arteries. It does not matter how strong the ventricles contract there will always be some blood left in to the ventricles after contraction. The amount of blood remaining in to the ventricles after contraction is known as End-Systolic volume

3. Isovolumetric Relaxation: Early Diastole:

After ventricular systole phase, the ventricle begins to relax; the pressure in the ventricle begins to decline. The pressure in the artery is now greater than that in the ventricle. Blood is now closing the semi-lunar valve as it tries to go from the artery into the ventricle preventing backflow. After the aortic valve closes aortic pressure rises due to back flow known as the dicrotic notch. Although the pressure in the ventricle is declining, but it is still greater than in the atria so the atrioventricular (AV) valves are still closed. As the ventricle is relaxing the volume of blood in the ventricle is not changing, so this stage will continue to do so until the ventricular pressure becomes lower than the atrial pressure and after that the filling stage starts all over again by opening AV valves.
So when our atria contracts it pushes blood in to the ventricles and there is something that separates our atrium from our ventricles and it’s called atrial ventricular or AV valve, so the AV valves will open and the atria will
Get Access