Yet the blood vessels, they extend from the surface of the brain down to reach every single cell in the brain, which means that fluid that's traveling along the outsides of these vessels can gain easy access to the entire brain's volume, so it's actually this really clever way to repurpose one set of vessels, the blood vessels, to take over and replace the function of a second set of vessels, the lymphatic vessels,
然而这些血管 却从大脑的表层延伸出来 到达大脑中的每一个独立的细胞， 这也就意味着，脑脊液 只要沿着这些血管的外壁流动 就可以轻易到达大脑中。 所以这就是，安排一套血管 去代替第二套如淋巴管一样功能 的一种巧妙办法。 这样就不需要 那另外的一套淋巴管了。