sphincter muscle of pupil

例句：

1. 1. The sphincter muscle ofthe pupil controls the amount of lightthat enters the eye.
   瞳孔括约肌控制着进入眼睛的光量。
2. 2. Insome species, the sphinctermuscle of the pupil can be usedto control the flow of tears.
   在一些物种中，瞳孔括约肌可以用来控制眼泪的流动。
3. 3. The sphinctermuscle of the pupil is essential formaintaining proper vision in humans.
   瞳孔括约肌对于人类保持正常视力至关重要。