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  1. Oct 30, 2023 · The cardiac cycle is defined as a sequence of alternating contraction and relaxation of the atria and ventricles in order to pump blood throughout the body. It starts at the beginning of one heartbeat and ends at the beginning of another. The process begins as early as the 4th gestational week when the heart first begins contracting.

    • Content Manager
    • 15 min
    • Atrial Systole. This phase is also known as presystole or the last rapid filling phage or atrial kick and is the phase when the atria contract to pump the blood out of the atria into the ventricles.
    • Ventricular Systole. It is the stage when the ventricle contracts expelling the blood outside of the ventricles. The Purkinje fibers relay the cardiac impulses all over the ventricular wall stimulating the ventricular wall to contract.
    • Protodiastole. It is the intermediary stage which indicates the end of systole and the beginning of the diastole stage. The ventricular ejection will have completely reduced the ventricular pressure making it lower than the blood pressure inside the major arteries.
    • Atrial Diastole. It is the stage when the atria are filled. During this stage, the AV valves are closed and the superior and the inferior vena cava pours in the deoxygenated blood collected from the body tissue to the right atrium; whereas the pulmonary veins bring the re-oxygenated (purified) blood to the left atrium.
  2. Oct 3, 2022 · The cardiac cycle is a series of pressure changes within the heart. These pressure changes result in blood movement through different chambers of the heart and the body as a whole. These pressure changes originate as conductive electrochemical changes within the myocardium that result in the concentric contraction of cardiac muscle. Valves within the heart direct blood movement, which leads to ...

    • Joshua D. Pollock, Amgad N. Makaryus
    • 2022/10/03
    • 2019
  3. Feb 23, 2023 · The cardiac cycle includes two parts, called diastole and systole, which are illustrated in Figure 10.4.1 10.4. 1. During diastole, the atria contract and pump blood into the ventricles, while the ventricles relax and fill with blood from the atria. During systole, the atria relax and collect blood from the lungs and body, while the ventricles ...

  4. The period of time that begins with contraction of the atria and ends with ventricular relaxation is known as the cardiac cycle (Figure 19.3.1). The period of contraction that the heart undergoes while it pumps blood into circulation is called systole. The period of relaxation that occurs as the chambers fill with blood is called diastole.

    • Lindsay M. Biga, Sierra Dawson, Amy Harwell, Robin Hopkins, Joel Kaufmann, Mike LeMaster, Philip Mat...
    • 2019
  5. Relate the heart sounds to the events of the cardiac cycle. The period from the start of one heartbeat to the start of the next, including both systole and diastole phases is known as the cardiac cycle. The contraction phase of the heart, during which blood is pumped into circulation is called systole. The relaxation phase of the heart, during ...

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  7. Jul 16, 2023 · The cardiac cycle can be divided into four stages: Filling phase – the ventricles fill during diastole and atrial systole. Isovolumetric contraction – the ventricles contract, but as the heart valves are shut, the volume remains constant. This causes a build-up of pressure, ready to propel blood into the aorta/pulmonary trunk.