In: Biology
Explain the steps of the cardiac cycle
Answer - The following steps are repeated in cyclic manner during cardiac cycle -
a) Auricular systole b) Ventricular systole
c) Joint diastole
Auricular systole - it means both atrium contraction.In this phase contraction of atrium takes place. When the Sino atrial node (SAN) generate action potential which stimulate and results into both atrium contraction simultaneously. Above process is auricular systole.
Ventricular systole - it means contraction is takes place in both ventricles.In this phase/step action potential is transmitted by Atrio ventricular node(AVN) and bundle of His in all over/entire heart walls. When the pressure increase cause bicuspid and tricuspid valves close rapidlyto prevent backflow of blood into atrium. They produce a 1st heart sound 'Lub' .
Joint diastole - it means relaxation. When the both article and ventricle in relax state. In this phase semilunar valves close rapidly. So produce second heart sound 'Dup'.