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Flashcards in The Cardiac Cycle Deck (11)
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What’s the relaxation phase of the heart



What’s the contraction phase of the heart



What happens during the diastole phase of the cardiac cycle

blood returns to the heart from the pulmonary vein and the vena cava

as the atria fill the pressure in them rises

when the pressure exceeds that in the ventricles the av valves open allowing the blood to pass into the ventricles

SL valves close to prevent the blood leaving the heart


What happens during atrial systole? ( contraction of atria)

Atria contract to push remaining blood into ventricles

Semi lunar valves closed

Left and right atrioventricular valves are open

Blood pumped from atria to ventricles

Ventricles remain relaxed


What happens during ventricular systole? ( contraction of the ventricles )

Semi lunar valves open

Left and right atrioventricular closed, as increase pressure, preventing backflow of blood

Ventricles contract and wall thickens - ventricles have a thick muscular walls which mean they contract around the body

Atria relaxed. Ventricles contract, pushing blood away from heart through pulmonary arteries and the aorta


What does the atrioventricular valves do

Between LA and LV and the RA and RV.

Prevents backflow of blood when contraction of the ventricles means that ventricular pressure exceeds atrial pressure

Closure of these ensures that, when the ventricles contract, blood within them moves to the aorta and pulmonary artery rather than back to the atria


What does the semi lunar valves do

In the aorta and pulmonary artery

Prevent backflow of blood into ventricles when the pressure in these vessels exceeds that in the ventricles


What do the pocket valves do

In veins

Ensure that when the veins are squeezed blood flows back towards the heart rather then away from it


What’s cardiac output

Volume of blood pumped by one ventricle or the heart in one minute


What does cardiac output depend on

Heart rate - rate at which heart beats

Stoke volume - volume of blood pumped out at each beat


Name the chamber of the heart that produces the greatest pressure

Left ventricle