primary medullary ray

例句：

1. 1. The primary medullary ray is responsible for transmittingnerve impulses from the spinal cord tothe brain.
   初级髓射线负责将脊髓神经冲动从脊髓传递到大脑。
2. 2. In thedevelopment of the nervous system, the primarymedullary ray plays acrucial role in the formation of myelin sheaths.
   在神经系统的发展过程中，初级髓射线在形成髓鞘中起着至关重要的作用。
3. 3. The primary medullary ray is an important component ofthe peripheral nervous system, providing sensory informationto the brain.
   初级髓射线是周围神经系统的重要组成部分，为大脑提供感觉信息。