What are the Three Phases of Cardiac Cycle in a Human Body?


If you are looking for the cardiac cycle stages, you have come to the right place. The cardiac cycle refers to the pumping action that your heart has while at rest. Performing a cycle is like pumping water through your house. It pumps the water through the pipes until it reaches the faucets. When you think of a water fountain, you think of a fountain that is running.

Phases of Cardiac Cycle

Basics of cardiac cycle phases:

The cardiac cycle is essential to proper cardiovascular function. It consists of the heart (heart valve) and cardiovascular system (vas deferens). The cardiovascular system supplies oxygen-rich blood to the tissues of the body while the heart pumps blood from the heart to the lungs’ vessels. The atria (venous chambers) allow nutrient-rich blood and waste products to flow from the capillaries and into the bloodstream through the valves in the heart.

Rate of a heartbeat:

The two semilunar valves help regulate the rate and rhythm of the heartbeat. The atria produce a positive pressure that pushes the blood through the veins and into the capillaries. This positive pressure also increases blood pressure. The ventricles react by contracting, decreasing and stopping the heartbeat. The atria and ventricles are separated by the atrial cavity, a thin space filled with air. The heart muscle actually rests on the atrium’s inner side and pumps the blood through this cavity.

As mentioned earlier, the Cardiac Cycle Phases are divided into three main phases: ventricular fibrillation (VF), tachycardia and ventricular tachycardia (VT). These three phases of the cardiac cycle occur when the hearts’ muscles are either too relaxed or too constricted. In turn, the atria expand to allow more blood to flow into the bloodstream and blood pressure raises.

There are four major functions of the ventricles in the cardiac cycle. First, as mentioned above, it provides positive pressure that causes the heart muscles to relax. Then there is the systole, a period when the heart is at rest, when the diastole phase occurs, during which the atria contracts and the ventricles relax.

Diastole period:

Finally, there is a diastole period where the heart stays at a lower level of blood filling after it has expanded to accommodate the increased blood flow. At this point, the ventricles are once again at full stretch with the ventricular rate beginning to increase, blood flowing towards the aorta, and the decrease in blood pressure occurs. As you can see, the ventricles’ major functions take place in both the atria and ventricular, with the systole taking place in the atria only. This makes the two phases of the cardiac cycle very different.

Other components:

The heart provides the strength and energy for the entire physiological system. It has been said that without the heart, there would be no life as we know it. Heart disease can affect all of us and even be fatal if left untreated. While it is true that the heart is the single largest organ in the human body, it is also made up of various components such as the diaphragm, chambers, valves, muscle fibres, nerves, other than the cardiac muscle itself. If any one of these other components becomes damaged or injured, then the organ’s functionality can be affected. As mentioned, the right ventricle is the cardiac cycle’s main muscle, pumping oxygenated blood from the lungs to the various parts of the body and the left ventricle is the backup muscle when the other parts fail.

The diastole or the slowing down of the diastole is an essential part of the cardiac cycle. As discussed previously, the diastole is a simultaneous occurrence. The normal way to tell whether the diastole has occurred is by watching the level of blood pressure in the cuff. If there is a marked decrease in the systole, then the diastole has occurred, and the heart is not pumping efficiently enough. To answer the question, the three phases of the cardiac cycle are the diastole, the systole, and the ventricular fibrillation (VF).

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Dr Carl Stephens

Hey, this is Carl. I’m a professional medical lecturer for students who want to learn how to get admissions, application sending methods, test preparation, etc.