Biology 3.1.2 Cardiac cycle

Question	Answer
Why does blood from the right ventricle have low pressure?	So that the capillaries aren't damaged by high pressures
What are the three stages of the cardiac cycle in order?	Atrial systole Ventricular systole Diastole
What happens during atrial systole?	The walls of the atria contract, forcing blood into the ventricles
What valve connects the arteries and ventricles?	Atrioventricular valve
What are the valves called in the aorta and pulmonary artery?	Semi-lunar valves
What happens during ventricular systole?	The ventricles contract
What do the elastic tissues in the walls of the ventricles do?	Recoil to stretch out to return ventricles to its original size
What causes the "lub-dub" sound of the heart beat?	The shutting of valves (atrioventricular=lub semilunar=dub) (sounds are in-order of which valve shuts first)
What keeps the valves from turning inside out?	Tendons

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	Created by Sam Gunnell about 5 years ago