Between these tentacle-like projections are tiny gaps called filtration slits that act like a sieve allowing only small particles such as water, glucose and ionic salts to pass through while blocking large proteins and red blood cells.

在这些触手状的突出物之间有微小的缝隙，称为滤孔；像筛子一样只允许小分子物质如水、葡萄糖、盐等通过，而阻挡大分子蛋白质、红细胞等。