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

睾酮的目标是最外层的细胞，称为原细胞。

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.

但是当青春期开始时，睾丸激素导致它们以不同的方式裂——而不是裂成两个相同的原细胞，它们开始产生两个不同的原细胞。

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.

考虑到有原细胞不断裂成母细胞，很容易看出一个成熟的男性是如何每秒产生 1500 个子的。

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。在整个童年时期，原细胞通过有丝裂不断裂成两个相同的子细胞。

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——也就是众所周知的 A 型细胞——会待在基底层附近并不断裂，所以原细胞永远不会耗尽。