Central Venous pressure and End diastolic pressur

[jsmith613]

Why does central venous pressure in the heart determine end diastolic pressure?
More importantly for me, why does end diastolic pressure determine end diasotlic volume (rather than volume determinine pressure)?
Thanks

[Chris90]

I think I have got an answer for why end diastolic volume is determined by end diastolic pressure . If you have a copy of Guyton and Hall medical physiology 12th edition , turn to page 108 , you will see a graph of left ventricular pressure (y axis) vs left ventricular volume (x axis) ,or just search for a pressure vs volume graph . During diastole as blood flows into the ventricles from the atria , the pressure in the ventricle slowly rises for the first 150ml of blood , then the gradient of the graph rises steeply and the pressure sharply increase for small increment of volume . This is because of the compliance of the cardiac muscle and that of the pericardium . The heart is to a certain extend stretchable and it stores potential energy in its wall the more its stretches and it tend to recoil back to its original state .

the more stretched the heart is the higher pressure it's wall exerts on the blood inside . This pressure opposes blood coming in from the atrium so as the more filled the ventricles , the harder it is for blood to move in from the atria . The pressure build in the ventricle determines the volume of blood entering it .