mjl1717
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Can anyone give "cold" a mathematical, in layman's terms, and in medical terms a definition of preload. Also what increase it and what decreases it. Thx in advance.
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| young_doc
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Preload is simply the amount of blood in the ventricles (of the heart) before it contracts. That's all it is! Honest! :P
Which is why we also call it EDV..or End Diastolic Volume...or volume of blood after diastole, or before systole (before contraction).
So what increases...well what would increase amount of blood in the heart? too much blood volume? too much venous return (blood returning to the heart)? too much blood left in the heart from a previous contraction (aortic/pulmonary regurgitation)?...
Be sure to also look at it in a pressur-volume curve. (BRS)
Hope this helps MJL.
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| mytime
Kick my butt!
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Preload is just that...pre...before.as after load is just that....after.And load u know.
Now it's about this happening on a particular muscle fiber...maybe skeletal or heart.it gives u the kick needed to get going.Think of it as when u stretch ur body and then u do ur work don't u acheive more?Afterload is more like the actual work load that u have to do.So when we stretch our bodies before a workout we givw it some preload to start with so as to get better results.In heart..the volume of blood that falls into the ventricle in relaxation time gives the preload...see its the same?And afterload is the pr achieved by contration of ventricles to overcome the aotic valve pr and eject blood.See the co-relation.Now go back and read it once again..it'll be clearer.
If u want more explaination ask.
We at the forum are ur preload and what u read is afterload. 
good Luck!
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