musculus sphincter

例句：

1. 1. The muscle sphincter is responsible for controlling the flow of bodily fluids.
   肌肉括约肌负责控制体液的流动。
2. 2. During sexual intercourse, the muscle sphincter helps to prevent premature ejaculation.
   在性行为中，肌肉括约肌有助于防止过早射精。
3. 3. The muscle sphincter plays a crucial role in maintaining the integrity of the digestive system.
   肌肉括约肌在维护消化系统完整性方面起着至关重要的作用。