It's here that oxygen molecules dissolve in the wet mucous, diffuse across the epithelial cells, and then cross the single layer of endothelial cells lining the capillaries to enter the bloodstream.

正是在这里，氧分子溶解在潮湿的粘液中，扩散穿过上皮细胞，然后穿过毛细血管内皮细胞的单层进入血液。