These guys can transform into ciliated columnar cells, so they help regenerate and replace damaged ciliated columnar epithelial cells if needed.

它们可以转化为纤毛柱状上皮细胞，必要时可以替代和修复受损的纤毛柱状上皮细胞。

From your stomach on down, though, the inner GI tract is lined with simple columnar epithelial cells, which secrete all sorts of stuff, and which absorb and process various nutrients.

然而，从你的胃开始，内侧胃肠道排列着简单的柱状上皮细胞，它们分泌各种东西，吸收和处理各种营养。

So the layer of stratified squamous and columnar epithelial cells that line your tract is actually a barrier between the outside world and your inside world — but it's a barrier that allows for the selective movement of materials between them.

所以这层复层的鳞状和柱状上皮细胞排列在你的肠道里，实际上是一个屏障连接了外界和你的内心世界——但这个屏障允许材料在它们之间有选择地移动。