Anatomy & Physiology第 81 / 100 题
Why is the left ventricle the thickest chamber of the heart?
a.It holds the largest volume of blood
b.It must generate enough pressure to pump blood through the entire systemic circulation
c.It contains the SA node and needs extra muscle to protect it
d.It receives blood directly from the venae cavae
解析
The left ventricle pumps against the high resistance of the systemic circuit, so its wall is roughly three times thicker than the right ventricle, which only pumps to the nearby low-pressure lungs. Both ventricles eject about the same volume per beat, so volume is not the reason. The SA node sits in the right atrium, and the venae cavae empty into the right atrium.
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