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    I need some help with the above topic . I am going to post the pic
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    I found this somewhere, is this the right answer?

    " When the pressure exerted by the heart onto the blood (and the ball) exceeds the pressure in the aorta, the ball is pushed away from the heart. This is the open position of the valve and blood can flow out of the heart into the aorta. After the heart ejects blood, the pressure inside the heart is greatly reduced so blood will try to flow back inside the heart. The negative pressure sucks the ball valve backwards. It fits over the opening of the heart and prevents backflow of blood"
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    (Original post by Laboromniavincit)
    I found this somewhere, is this the right answer?

    " When the pressure exerted by the heart onto the blood (and the ball) exceeds the pressure in the aorta, the ball is pushed away from the heart. This is the open position of the valve and blood can flow out of the heart into the aorta. After the heart ejects blood, the pressure inside the heart is greatly reduced so blood will try to flow back inside the heart. The negative pressure sucks the ball valve backwards. It fits over the opening of the heart and prevents backflow of blood"
    Firstly, the question refers to valve 4, the mitral valve, not the aortic valve which is valve 3 on the diagram. What you've said would be correct if the artificial valve replaced the aortic valve though, so the idea is correct. The part of the artificial valve labelled A should point towards the left ventricle. When the left atrial pressure is greater than the left ventricle (during diastole) the ball moves towards A and the valve opens, allowing blood to flow into the left ventricle. When the left ventricular pressure exceeds that of the left atrium, the ball moves back towards B, the closed position, preventing regurgitation of blood from the left ventricle into the left atrium.
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    (Original post by Laboromniavincit)
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    Ah, the old "Starr-Edwards valve", long since discontinued, still makes its appearance in Biology exams!

    Essentially in this valve blood flows from B to A, so if it is a mitral valve replacement B would be in the left atrium and A in the left ventricle, and if it is used as aortic valve then B would in the left ventricle and A in the aorta. There is always a little bit of regurgitation (otherwise ball wouldn't move back)

    The reason for any valve opening in the heart is because of the pressure gradient. There is no negative pressure involved.
    The pressure in the aorta ranges from 80 (diastolic) to 120 (systolic), and the pressure in the left ventricle 4 (diastole) - 120 (systole), while the pressure in the left atrium is 4 - 12.
    When the pressure in one chamber is greater than the next then the valve opens, if the next chamber's pressure is greater there is a bit of backflow and the valve closes.
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    Thank you so much
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    Thank you both
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