1.But nature's full of exceptions, and strangely, some animals have lost their anuses.

但是自然界充满了例外，奇怪的是，有些动物失去了肛门。

2.As varied as the animal kingdom's anuses are, none of them have bones.

尽管动物王国的肛门种类繁多，但没有一个肛门是有骨头的。

3.Brittle stars and many parasites had ancestors with anuses, but no longer have them.

海蛇尾许多寄生虫的有肛门，但现在已经没有了。

4.Instead, from the gut, bacteria get to the rectum, anus and eventually colonizes the perineum, becoming part of the normal flora.

相反，细菌由肠道到达直肠、肛门，终定居于会阴，成为正常菌群的一部分。

5.Hemorrhoids are swollen veins near the anus and rectum, which can be painful and lead to itching and bleeding.

痔疮是肛门直肠附近的肿胀静脉，会引起疼痛并导致瘙痒出血。机翻

6.Specialized tube feet can be used for feeding and respiration, though many sea cucumbers actually breathe through their anuses.

专门的管脚可用于进食呼吸，尽管许多海参实际上是通过肛门呼吸的。机翻

7.A sea cucumber is essentially a brainless, fleshy form surrounding a digestive tract, bookended by a mouth and an anus.

海参本质上是一种无脑的肉质形式， 围绕着消化道，由嘴巴肛门构成。机翻

8.Treatment is typically surgical resection of the area that's lacking the nerve fibers, and then the healthy end is connected to the anus.

治疗疾病一般行根治手术，切除神经纤维缺失的肠段，然后将剩余肠段健康的一端连肛门。

9.The most widely-used definition of deuterostome has to do with how our mouths and — the SciShow comments’ favorite term — anuses develop.

泛使用的后口动物定义与我们的嘴巴——SciShow 评论喜欢的术语——肛门的发育方式有关。机翻

10.Extending from the end of the ileum to the anus, it is divided into four parts: cecum, colon, sigmoid colon and rectum.

大肠从回肠末端延伸到肛门，并分为四个部分：盲肠，结肠，乙状结肠直肠。

11.Certain species of crabs and pearlfish take advantage of this rhythmic action and, once the sea cucumber's anus is dilated, they shimmy in and take shelter.

某些种类的螃蟹珍珠鱼利用这种有节奏的动作，一旦海参的肛门扩张， 它们就会潜入并躲避。机翻

12.Unlike its cousin, ulcerative colitis, which only affects the large intestine, Crohn disease causes inflammation and tissue destruction anywhere along the gastrointestinal tract, from the mouth to the anus.

虽与溃疡性结肠炎同属炎症性肠病，但溃疡性结肠炎只侵犯大肠，而克罗恩病能引起胃肠道任何部位的炎症组织破坏，上至口腔，下达肛门。

13.We — and all animals from the simplest worms on up the Tree of Life — are really just tubes, corridors of tissue running from a mouth to an anus.

我们——以及生命之树上简单的蠕虫——实际上只是管子，从嘴到肛门的组织走廊。

14.By loosening the attachments of internal tissues then quickly softening and contracting their muscles, many species are capable of shooting a wide range of organs out of their anuses.

通过松开内部组织的附着物，然后迅速软化收缩它们的肌肉，许多物种都能够从它们的肛门中射出范围泛的器官。机翻

15.Now if we zoom into a cross-section of the rest of the gastrointestinal tract, anywhere from the esophagus till the anus, the walls are typically lined by the same four layers of tissue.

现在，我们把其余消化道的横截面放大来看，即从食管到肛管的部分，其管壁通常都由相同的四层组织构成。

16.In fact, the enteric nervous system, which is an extensive mesh-like network of neurons that controls your entire digestive tract from the esophagus to the anus, doesn't even require the brain at all.

事实上，肠道神经系统是一个由神经元组成的网状网络，控制着从食道到肛门的整个消化道，它甚至不需要大脑控制。

17.Anatomically, the digestive system consists of a 30-foot long, mucous membrane-lined tube beginning with the mouth, where food enters the body, and ending with the anus, where solid waste is excreted.

在解剖学上，消化系统由一个30英尺长的内面由粘膜覆盖的管道组成，食物从管道的起始处-口进入体内，固体代谢废物在管道的末尾处-肛门排泄出去。

18.In fact, the enteric nervous system, which is an extensive mesh-like network of neurons that controls your entire digestive tract from the esophagus to the anus, doesn’t even require the brain at all.

事实上，肠神经系统是一个泛的网状神经元网络，控制着从食道到肛门的整个消化道，它甚至根本不需要大脑。机翻

19.The rectum serves as a reservoir for feces. It terminates in the lower opening of the gastrointestinal tract, the anus, which is the external opening through which feces are released from the body.

直肠作为粪便的容器，终止于胃肠道的下部开口，即肛门，肛门是粪便从身体排出的外部开口。

20.Now, I'm quite sure that you're familiar with the key players here — they're the hollow organs that form the continuous tube that is your alimentary canal, aka the gastrointestinal tract, which runs from your mouth to your anus.

现在，我很确定你对这里的关键选手很熟悉——它们是形成连续管子的中空器官，也就是你的消化道，也就是胃肠道，从你的嘴延伸到你的肛门。