Question

Put these phases of the cardiac cycle in the correct order. 1. opening of the semilunar valves 2. isovolumic contraction 3. beginning of atrial systole 4. closure of the AV valves 5. completion of ventricular filling 6. beginning of ventricular systole 7. ventricular relaxation 8. ventricular ejection

Answer 1

The Cardiac cycle

Explanation:

Correct order is: 3,5,6,4,2,1,8,7

The cycle of events that happen in a single heart beat is called Cardiac cycle. Basically, it refers to repeated pattern of contraction and relaxation of the heart.The contraction of heart is called systole and the relaxation of heart is called diastole. The cardiac cycle includes systole and diastole of atria as well as systole and diastole of the ventricles. When heart rate is about 75 beats per minute, a cardiac cycle takes 0.8 seconds.

The order of events is cardiac cycle is :

• beginning of atrial systole
• completion of ventricular filling.
• beginning of ventricular systole.
• closure of AV valve.
• isovolumic contraction.
• opening of semilunar valve.
• ventricular ejection.
• ventricular relaxation.