The urethra is a thin muscular tube that drains urine from the bladder, starting from the internal urethral orifice to the external opening.

尿道是细的肌性管道，从膀胱引流尿液；起于尿道内口，终于尿道外口。

They have a system of external openings called spiracles, that lead to a branching network of tubes called tracheae, that diffuse oxygen through their bodies.

它们有一个称为气孔的外部开口系统，通向一个称为气管的分支网络，通过它们的身体扩散氧气。

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。