The targets of the testosterone are the outermost cells in the tubules, called spermatogonia.

睾酮的目标小管中最外层的细胞，称为精原细胞。

But when puberty starts, the testosterone causes them to divide differently — instead of splitting into two identical spermatagonia cells, they begin producing two distinct spermatogonia.

当青春期开始时，睾丸激素导致它们以不同的方式裂——而不裂成相同的精原细胞，它们开始产不同的精原细胞。

And considering how many spermatogonia are continuously dividing into spermatocytes, it's easy to see how a mature male can crank out 1500 sperm a second.

考虑到有多少精原细胞不断裂成精母细胞，很容易看出一成熟的男性如何每秒产 1500 精子的。

And actually, they've been doing that all along — even before puberty. Throughout childhood, a spermatogonia cell uses mitosis to continuously divide into two identical daughter cells.

事实上，它们一直都在这样做——甚至在青春期之前。在整童年时期，精原细胞通过有丝裂不断裂成相同的子细胞。

One type of daughter cell — known as a type A cell — stays up near the basal lamina and just keeps dividing, so you never run out of spermatogonia.

有一种子细胞——也就众所周知的 A 型细胞——会待在基底层附近并不断裂，所以精原细胞永远不会耗尽。