But in this case, the sperm develop on the outer edge of the tubule, and progress inward toward the lumen.

但是情况下，精子小管的外缘发育，并向内前进。

The apical or upper side, is exposed to either the outside of your body, or whatever internal cavity it's lining.

顶端或上部，暴露你身体的外部或它的任何内中。

This causes a decreased blood flow through its lumen, or hollow center.

导致通过其内或中空中心的血流减少。

Most of your blood vessels share a similar structure consisting of three layers of tissue surrounding the open space, or lumen, that actually holds the blood.

你的大多数血管都有一个相似的结构，由织成，围绕着开放空间或内，实际上容纳血液。

Anatomists call these layers " tunics, " and the innermost section is the tunica intima — which should be pretty easy to remember because, you know, it has like intimate contact with the lumen. It's like your circulatory underpants.

解剖学家称些为束腰外衣，最里面的部分是内膜——应该很容易记住，因为，你知道，它和内有亲密的接触。就像你的循环内裤。