為什么嘴唇會干呢?
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. Basically, our lips are made of the same mucusmembrane that coats the inside of our mouths. This means two things.
First, our lips don’t have the same protective outer layer as the skin elsewhere on our bodies. This layer is part of the barrier to evaporation, and its absence means our lip skin retains less fluid. Second, our lips don’t have the same glands and pigments as ordinary skin. 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.
What this means is that our lips have little to no protection from the environment, and their main source of moisture is the saliva that comes from our mouths. What’s more, unlike much of the rest of our body, our lips are almost always on display, and rarely covered by clothing. As a result, the moisture on our lips is continually evaporating. And that’s before we take into account exposure to sun, wind, cold, and air-conditioning. Plus, if you’re sick or have allergies, and your nose is congested, your lips end up drying more quickly because you tend to breathe through your mouth.
首先,我們需要知道嘴唇的表皮有別于身體其他部位的?;径?,嘴唇有相同的粘液膜組成,保護我們的嘴巴。這就說明了兩件事首先。
第一,我們身體其他部位的肌膚有一層“保護層”,這是嘴唇所沒有的。“保護層”能有效保濕,嘴唇因為沒有而不易保濕。第二,嘴唇不像其他肌膚有腺體和色素。比如,嘴唇不能分泌油脂,不易保濕。此外,嘴唇缺少黑色素等色素保護皮膚免受太陽灼傷。
這就說明嘴唇易受環(huán)境影響,而嘴唇水分大多來源于嘴里的唾液。此外,嘴唇有別于身體其他部位的皮膚(有衣蔽體),嘴唇經(jīng)常暴露在外面。這樣一來,嘴唇的水分一直在蒸發(fā),這還不算陽光、大風、天冷、空調(diào)的“摧殘”。此外,如果你生病了或者過敏而鼻塞,不得不用嘴巴呼吸,嘴唇會干得更快!