Question

Which of the following events does not take place during a ventricular systole
i. Due to the ventricular systole, ventricular pressure decreases.
ii. During the end of ventricular systole the semilunar valves open up.
iii. During the start of the ventricular systole the bicuspid and tricuspid valves close
iv. Due to the closure of the atrio-ventricular valves, dup sound is produced.

• A. Event 1, 2 does not take place
• B. Event 2, 3 does not take place
• C. Event 1, 4 does not take place
• D. All events take place

Answer 1

The correct option is C Event 1, 4 does not take place

Ventricular systole is a stage in cardiac cycle where the left and right ventricles contract at the same time and pump blood into the aorta and pulmonary trunk, respectively.

The pressure inside the ventricles increases during ventricular systole and this results in closure of the bicuspid and tricuspid valve. The closure of these atrioventricular valves produces the lubb sound.

As the pressure inside the ventricles increases, the semilunar valves open up and blood is released into the systemic circulatory system. After this stage the pressure inside the ventricles falls and the ventricles relax. The semilunar valve close during the end of the ventricular diastole. The closing of the semilunar valves produce the dup sound.