Both of these are called diffusible because they're small enough to diffuse across cell membranes.

这两者都被称作可扩散，它们的体积足够小，可以穿过细胞膜完成扩散。

Sometimes though, total calcium levels in the blood, which includes both diffusible and non-diffusible - in blood can vary a bit, depending on the blood's pH and protein levels.

有时候，血液中的总水平包含了可扩散和非扩散，着血液pH值和蛋白水平的改变而有一些波动。

Now, the majority of the extracellular calcium, the calcium in the blood and interstitium, is split almost equally between two groups - calcium that is diffusible and calcium that is not diffusible.

那些在血液和间质中的大多数细胞外被大致均分成两组：可扩散与不扩散。