Answer:
1. Isovolumetric relaxation.
2. Ventricular filling.
3. Isovolumetric contraction.
4. Ventricular ejection.
5. Ventricular filling.
6. Ventricular ejection.
7. Isovolumetric contraction.
Explanation:
In Human anatomy, cardiac cycle can be defined as a complete heartbeat of the human heart which comprises of sequential alternating contraction and relaxation of the atria and ventricles, therefore causing blood to flow unidirectionally (one direction) throughout the human body.
Generally, the cardiac cycle occurs in two (2) stages;
- <em>Diastole</em>: in this stage, the ventricles is relaxed and would be filled with blood.
- <em>Systole</em>: at this stage, the muscles contracts and thus, allow blood to be pushed through the atria.
The following terms describe the physical or mecahnical events with the correct phases of the cardiac cycle in mammals (human beings).
1. Isovolumetric relaxation: All 4 cardiac valves are closed and all 4 chambers are relaxed during this phase.
2. Ventricular filling: The maximum amount of blood is in the ventricles at the end of this phase.
3. Isovolumetric contraction: The pressure in the ventricles is higher than in the atria, but lower than in the arteries, during this phase.
4. Ventricular ejection: The semilunar valves are open and the AV valves are closed during this phase.
5. Ventricular filling: The atria contract at the end of this phase.
6. Ventricular ejection: The pressure in the ventricles is higher than the pressure in both the atria and the arteries during this phase.
7. Isovolumetric contraction: Systole begins with this phase.
