字幕列表 影片播放 列印英文字幕 Smart Learning for All. Topic: Chapped lips. What causes chapped lips? Making weird faces. No. Our lips are very sensitive. This is because the outermost layer of our skin called stratum corneum is much thinner on our lips than on any other body parts. As it is thinner, the blood vessels inside them are more prominent making our lips appear reddish or pinkish. Besides this, the skin on our lips doesn't have oil and sweat glands which secrete substances to moisturize the lips. Hence, our lips have very less moisture. Now, usually during cold months, as the air has less moisture, the moisture from our lips evaporates causing them to get dry and chapped. So to provide moisture, we can lick our lips and apply saliva. No. Saliva draws more moisture and heat from our lips and evaporates, thus leaving our lips more drier than before and thus, making the condition worse. For more educational videos please visit http://www.SmartLearningforAll.com Also, don't forget to subscribe to our YouTube channel.