Question

explain the process of cardiac cycle..

question is for 8 marks so need long answer​

Answer 1

hiii buddy

here is your answer

• cardiac cycle comprises a complete relaxation and contraction of both the atria and ventricles
• and it lasts approximately for 0.8seconds
• beginning with all the chambers
• in diastole blow flows passively from the veins into atria
• and pass the atriventricular vavles into ventricles

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Answer 2

Answer:

Explanation:

➛ Cardiac cycle refers to the the repeating contraction (systole) and relaxation (diastole) of the heart

➛ Each cycle of atrial and ventricular systole and diastole last for about 0.8 second.

Main characteristics of the cardiac cycle:

➜ At the onset of the ventricular contraction, the atrioventricular valves close and the semilunar valves open producing the lub sound. The interval between the closing of the AV valves and opening of the semilunar valves is called as the isometric contraction period. The ventricles contract thus resulting in the increase of intraventricular pressure during this period.

➜ At the onset of the ventricular relaxation, the semilunar valves close and the AV valves open producing the dub sound. The interval between the opening of AV valves and closure of semilunar valves is called the protodiastolic pressure.

➜ As the ventricles relax, the intraventricular pressure decreases and the AV valves open. This is called isometric relaxation which usually lasts for about 0.08 second. As a result, blood flows into the ventricles. This indicates the beginning of ventricular filling.

➜ The first part of the filling is known as the first rapid filling phase. The intermediate part is slow and is known as the slow inflow phase or diastasis. This is the longest filling phase. During this phase, blood flows from vena cava to the ventricles.

➜ The last part of ventricular filling is the last rapid filling phase.  The rapid blood flow is due to the increased arterial pressure. It occurs in overlapping with arterial systole. Here ventricular diastole ends and systole starts ends. Hence, the cycle continues.

Heart sounds:

• Lub: Low pitched sound caused by the closure of AV valves at the onset of ventricular systole.
• Dub: High pitched sound caused by the closure of semilunar valves at the onset of ventricular diastole.