So for example, let's imagine that we have a build up of pressure here. And so the fluid pushes against the overlapping portion and the fluid moves into this cavity, this region of our lymph vessel. Now, as the fluid builds up in the lymph vessel, it pushes back onto this side, the other side of our endothelial cell. And because these endothelial cells open only one way and not the other way, when our hydrostatic pressure pushes on our cells this way, the fluid cannot escape back because these overlapping regions between the cells only open this way and not the other way. And we also have a system of one way valves found along the lymph vessel. So that means these valves also open one way and not the other way.