These parasympathetic neurons make the rectum contract and the internal anal sphincter relax.

这些副交感经元可以使直肠收缩，并使肛门内括约肌松弛。

During life's three billion-plus year journey on Earth, anal evolution happened independently many times in different branches of life.

在生命在地球上 30 亿多年的旅程中，肛门进化在不同的生命分支中独立发生了许多次。

The gastrointestinal tract is made up of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and finally the anal canal.

消化道的构成包括：口腔、咽、食管、胃、小肠、大肠以及肛管。

Symptoms of cauda equina include decreased bowel and bladder control due to a decreased tone of anal sphincters and muscle wall of the bladder and decreased sexual function.

经综合征的症状，包括排便和膀胱控制力；这是由肛门括约肌和膀胱壁肌肉张力降引起的，以及性降。

Meanwhile, signals are sent to the brainstem and thalamus, and when these decide the right moment has come, they allow the external anal sphincter to relax - and feces goes, hopefully, into the toilet bowl.

直肠发出的信号同时也发送到了脑干和丘脑；当它们认定“时机成熟”时，便会达指令使肛门外括约肌松弛；粪便就——不出意外的话——顺利排入桶。

So, for instance, there's no evidence that oral and anal characteristics, the personality characteristics I talked about – about being needy versus being stingy – relate in any interesting way to weaning or toilet training.

因此，例如，没有证据表明口腔和肛门的特征，我谈到的性格特征——关需要和吝啬——以任何有趣的方式与断奶或如厕训练相关。

Just the anal vampire who can't stand mess and wants everything to be structured and needs to have a regiment and has to make a chore wheel so that everyone keep on top of doing the dishes or vacuuming.

只有肛门吸血鬼无法忍受混乱，希望一切都井井有条，需要有一个团，必须做一个家务轮子，这样每个人都继续洗碗或吸尘。

If it starts to rot, or you start to snack on this body, you'll have to cover the stench of decomposition with your own anal secretions so that other hungry, desperate, overworked parents don't come looking for your lunch.

如果它开始腐烂， 或者你开始在这个身体上吃零食，你就必须用你自己的肛门分泌物来掩盖腐烂的恶臭， 这样其他饥饿、绝望、过度劳累的父母就不会来找你的午餐了。