The Heart 3B Flashcards
Which ventricle has a thicker wall
left ventricle as it pumps blood to the who body
What has thicker walls the atria or the ventricles
Ventricles as they have to push blood out of the heart
What do atrioventricular valves do
link the atria to the ventricles and stop blood flowing back to the atria when ventricles contract
What do semi lunar valves do
link the ventricles to the pulmonary artery and the aorta and stop blood flowing back into the heart when ventricles contract
What do the cords which attach the atrioventricular valves to the ventricles do
Stop the valves from being forced back into the atria when the ventricles contract
What happens if there is a higher pressure behind a valve
it is forced open
What happens if there is a higher pressure in front of a valve
it is forced shut
What happens during stage one of the cardiac cycle
Ventricles relax, atria contract
Decreasing the volume of the chambers and increasing the volume of the chambers
This pushes blood into the ventricles and there is a slight increase in ventricular pressure and chamber volume
What happens during stage 2 of the cardiac cycle
Ventricles contract and the atria relax. Ventricles contract decreasing their volume , increasing their pressure
Higher pressure in ventricles than atria AV valves shut
pressure in ventricles is higher than in the pulmonary artery or the aorta which opens SL valves and blood is forced into the arteries
What happens during stage 3 of the cardiac cycle
Ventricles and atria relax higher pressure in pulmonary artery and the aorta closes SL valves blood returns atria fill again due to higher pressure in pulmonary vein and pulmonary artery pressure of atria increases and as the ventricles begin to relax their pressure falls below the pressure of the atria so the AV valves open this allows blood to flow passively into the ventricles the atria contract and the cycle starts again
