tectum

例句：

1. 1.The tectum is the outer layer of the skin.
   角质层是皮肤的外层。
2. 2.The tectum protects the brain from injury.
   角质层保护大脑免受损伤。
3. 3.The tectum is responsible for temperature regulation in the body.
   角质层负责调节身体的温度。