On the other side of the pneumocytes are endothelial cells that line the capillary walls, which is what holds the blood.

而肺泡细胞的另一边就毛细血管壁的内皮细胞，毛细血管携带的便我们亲爱的血液。

High blood pressure is a serious problem for the blood vessels because it causes wear and tear on the endothelial cells that line the inside of the blood vessels.

高血血管来说一种很严重的疾病，因为它会导致血管壁内皮细胞的破坏及撕裂。

The thread-like fibers we see — thinner than a human hair — are the remains of those dense, dried out walls of cellulose.

我们到的丝状纤维（比人类毛发还要细）那些紧实干燥的纤维素壁（原细胞壁）的残留物。

It starts out as an empty protein packet sent out by the liver to gather up other cholesterols from the blood, and artery walls, and other cells.

它肝脏发出的一个空蛋白质包，用来收集血液中的其他胆固醇，动脉壁和其他细胞。

They do build a new, permanent, cellulose wall to separate parent cells from their offspring, though.

不过，它们确实建立了一个新的、永久的纤维素壁，将亲本细胞与后代细胞分开。

Now these free-floating platelets don't clump together during regular circulation — that would be terrible — but when the endothelial cells lining a blood vessel wall tear, the underlying collagen fibers are suddenly exposed.

这些自由漂浮的血小板在正常的血液循环中不会凝结在一起——那太可怕了——但当血管壁内皮细胞撕裂时，其底层的胶原纤维突然暴露出来。

Yeah, the cells, if you think of the walls of the cells, they make the tree strong and there are a couple of chemicals that make up these walls, cellulose and lignin.

的，细胞，如果你想到细胞的壁，它们使树木强壮， 这些壁由几种化学物质构成，包括纤维素和木质素。

So the endothelium is the single layer of cells that line every blood vessel throughout the body.

因此，内皮遍布全身每条血管壁的单层细胞。

And these are literally bacterial cell walls that are going through the wall of our gut.

而这些实际上穿透我们肠道壁的细菌细胞壁。