Let's start by reviewing the ways in which the surface of our lips is different from the surface of the skin on the rest of our bodies.
我们首先看下嘴唇表面与我们的身体其余部分皮肤的不同。
Basically, our lips are made of the same mucus membrane that coats the inside of our mouths.
基本而言,我们的嘴唇由保护我们嘴部的相同粘液膜组成。
This means two things.
这意味着两件事。
First, our lips don't have the same protective outer layer as the skin elsewhere on our bodies.
首先,我们的嘴唇没有同身体相同的外层保护皮肤。
This layer is part of the barrier to evaporation, and its absence means our lip skin retains less fluid.
这一层能够抵挡水分蒸发,而它的缺乏意味着我们的嘴唇皮肤只能留存较少的液体。
Second, our lips don't have the same glands and pigments as ordinary skin.
第二,我们的嘴唇没有普通的皮肤所具有的腺体和色素。
For example, lips don't have oil glands, which also help keep moisture from evaporating, and they contain less melanin, the pigment that helps protect our skin from sunburn.
比如嘴唇没有也有助于防止水分蒸发的油腺,而且嘴唇含有更少的黑色素,这种色素能够帮助保护皮肤免受太阳灼伤。
