Cardiac Cycle

Question 1

What happens in the atrial systole?

Answer 1

Blood enters the atrium meaning the atrial pressure is higher than the ventricular pressure
Meaning the AV valves remain open while the atria contracts
This pushes the blood into the ventricles

Question 2

What happens in the ventricular systole?

Answer 2

•the blood fills the ventricles •their walls begin to contract •increasing the pressure rapidly
•Once the ventricular pressure rises above the major arteries the semi lunar valves are forced open
•slight delay between sl valve opening and av valve closing
•increasing the ventricular pressure
•causes blood to spurt into aorta
•increasing the aortic pressure
•elastic tissues in the arterial walls stretch and recoil
•this evens out the pressure for the tissues

Question 3

What happens in the diastole?

Answer 3

Following systole the ventricular walls relax and the pressure drops bellow the major arteries pressure
Meaning the semi lunar valves closes
When the ventricular pressure then drops bellow the atrial pressure the AV valve opens

Question 4

What are the opening and closing of valves controlled by?

Answer 4

Pressure change