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    Is this okay for the cardiac cycle?

    Diastole - Atria and Ventricles relax
    -Blood flows from veins to atria.
    -This causes pressure in atria to increase so AV valves forced open and blood trickles into ventricles.

    Atrial Systole - Atria contract
    -This forces all blood into ventricles.

    Ventricular Systole - Ventricles contract
    -Contraction creates higher pressure in ventricles than atria so AV valves forced shut.
    -This pressure also forces semi lunar vales open so blood moves into arteries.
    -Higher pressure in arteries than ventricles now forces semi lunar valves shut.

    Repeat



    I've highlighted bits that I'm particularly confused about.
    Thanks!
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    (Original post by Qaiys)
    Is this okay for the cardiac cycle?
    -Contraction creates higher pressure in ventricles than atria so AV valves forced shut.
    Heya,

    The AV valves are between the atria and ventricles. They only open one way, so when pressure is higher in the atria compared to the ventricles, blood is forced through them. However, when pressure is higher in the ventricles, they snap shut, because they can't open the other way. Think of a standard door: it only opens one way, and can't open the other. Understandably, there are conditions where the valve can 'prolapse', so when it does open the other way too, and this has to be fixed. In a normal heart, there are tendons which attach to the valves and pull the valves down as the ventricle contracts to stop this prolapse.

    (Original post by Qaiys)
    -Higher pressure in arteries than ventricles now forces semi lunar valves shut.
    Again, it's the same principle (but there are no tendons this time!). The valves only open one way in normal people, so blood rushing backwards into the heart will force the valves shut. Again, some people do have problems with this, and this is usually repaired.

    Hope this helps!
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    (Original post by Harantony)
    Heya,

    The AV valves are between the atria and ventricles. They only open one way, so when pressure is higher in the atria compared to the ventricles, blood is forced through them. However, when pressure is higher in the ventricles, they snap shut, because they can't open the other way. Think of a standard door: it only opens one way, and can't open the other. Understandably, there are conditions where the valve can 'prolapse', so when it does open the other way too, and this has to be fixed. In a normal heart, there are tendons which attach to the valves and pull the valves down as the ventricle contracts to stop this prolapse.


    Again, it's the same principle (but there are no tendons this time!). The valves only open one way in normal people, so blood rushing backwards into the heart will force the valves shut. Again, some people do have problems with this, and this is usually repaired.

    Hope this helps!
    Thanks a lot! Apart from that is the rest of the cycle okay and in the right order and stuff?
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    (Original post by Qaiys)
    Thanks a lot! Apart from that is the rest of the cycle okay and in the right order and stuff?
    Sorry for the super late reply! Yep, the ordering and stuff looks OK to me.
 
 
 
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