It contains microscopic, fluid-filled tubules that run from the pulp to the underside of the enamel.

它包含微小的、充满液体的小，从牙髓一直到牙釉质下层。

If your enamel is worn away, your dentin and its tubules can be exposed.

如果你的牙釉质被磨掉了，你的牙本质和它的小就会暴露出来。

These tubules are the sperm factories, made of a stratified epithelium surrounding a central fluid-filled lumen.

这些小是精子工厂，由围绕充满液体的腔的分层上皮组成。

And this sperm-making work is supported by cells throughout and around the tubules.

这种精子制造工作是由遍布小及其周围的细胞支持的。

Each one is divided into about 250 sections, called lobules, which are loaded with tightly-coiled seminiferous tubules.

每一个都被分成大约 250 个分，称为小叶，其装载着紧密盘绕的生精小。

ADH affects the last two-thirds of these tubes, called the distal convoluted tubule and the collecting ducts.

ADH作用于这些小的2/3分，即远曲小和集合。

Typically intrarenal AKI's due to damage to the tubules, the glomerulus, or the interstitium —the space between tubules.

通常，肾性AKI是由于肾小、肾小球或间质空间（肾小间的空间）损坏所致。

Beneath that is the medulla, a set of cone-shaped masses of tissue that secrete urine into tiny sac-like tubules.

髓质下面是一组锥形组织，将尿液分泌到微小的囊状小。

It's called a cast because it stays in essentially the same cylindrical shape as the tubule.

它被称为型，是因为它基本上与小保持相同的圆柱形状。

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

睾酮的目标是小最外层的细胞，称为精原细胞。

As the filtrate leaves the Bowman's capsule it flows into the renal tubule, which is surrounded by the peritubular capillaries.

滤液离开肾小囊后流入肾小，后者被周毛细血网包围。

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

但是在这种情况下，精子在小的外缘发育，并向内腔前进。

And this is showing us the digestive tubules of these animals.

这向我们展示了这些动物的消化。

And they also have a circulatory system that wraps around that tubule.

它们还拥有一个环绕该状结构的循环系统。

Things like specific organizational structures are the cells forming gland-like tubules or papillary clusters.

像特定的组织结构，例如形成腺样状结构或乳头状簇状的细胞。

So, let's trace the whole process, starting at the top, with the proximal convoluted tubule or PCT.

所以，让我们追踪整个过程，从顶开始，用近端卷曲小或 PCT。

Macula densa cells are located in the distal convoluted tubule and they can sense when levels of sodium and chloride are low.

致密斑位于远曲小，可以感受到钠和氯水平降低。

Now, that calcium's still in the lumen, but parathyroid hormone also affects the distal convoluted tubule and increases calcium reabsorption.

这时，钙仍然在腔内，但甲状旁腺激素也会影响远曲小，增加对钙的再吸收。

Some substances are removed from blood through the peritubular capillary network into the distal convoluted tubule or collecting duct.

有些物质通过周毛细血网从血液移出，进入远曲小或集合。

Now, obviously, if sperm are going to get anything accomplished, they have to leave the seminiferous tubules that made them.

现在，很明显，如果精子想要完成任何事情，它们必须离开制造它们的生精小。