Cell Turnover细胞更新

Did you know that the skin creates its own body armor? The skin is our body's biggest organ and acts like a shield. It's constantly changing and renewing itself, which is really important for keeping it strong and working well. Wicket and Visscher (2006) explain how this works.
你知道皮肤会为自己制造身体护甲吗？皮肤是我们身体最大的器官，像盾牌一样起作用。它不断变化和自我更新，这对保持其强健和正常工作非常重要。Wicket 和 Visscher（2006）解释了这是如何运作的。

How a Skin Barrier is Created
皮肤屏障的创建方式

At the center of this is something called epidermal turnover. It starts in the deepest layer of the skin, the stratum basale. Here, new skin cells keep forming and push the old ones towards the surface. As these cells move up, they go through a change called keratinization, where they harden and die. This might sound bad, but it's actually good because these tough cells make a protective layer for our skin.
这一切的核心是被称为表皮更新的过程。它始于皮肤的最深层，即基底层。在这里，新的皮肤细胞不断形成，并将旧细胞推向表面。当这些细胞向上移动时，它们会经历一个称为角蛋白化的变化，在这个过程中它们会变硬并死亡。这听起来可能不好，但实际上是好的，因为这些坚韧的细胞为我们的皮肤形成了一层保护层。

The process finishes when these old cells are shed from the skin. This lets new, fresh cells come to the surface. This cycle of old cells leaving and new ones arriving is very important for keeping our skin healthy and able to protect us.
这个过程在旧细胞从皮肤脱落时完成。这使新的、新鲜的细胞能够到达表面。这种旧细胞离开、新细胞到来的循环对我们的皮肤健康和保护我们非常重要。

Factors That Influence the Skin Barrier
影响皮肤屏障的因素

Different factors can affect this process. Factors outside of the skin, like sunlight, wind, or even scratching, can have an impact. Also, as we get older, this process slows down, which can change how our skin looks because there are now more dead cells on the skin's surface than in the case of healthy, younger skin. This influences its ability to protect us.
有多种因素会影响这一过程。皮肤外部的因素，如阳光、风，甚至抓挠，都可能产生影响。此外，随着年龄的增长，这一过程会变慢，这会改变皮肤的外观，因为与健康、年轻的皮肤相比，皮肤表面有更多的死细胞。这影响了其保护我们的能力。

How the Skin Barrier Stays Healthy
皮肤屏障如何保持健康

Two important things help strengthen our skin barrier: ceramides and natural moisturizing factor (NMF). Ceramides are special fats in our skin that help keep it moist and strong. They work like the mortar in a brick wall, holding everything together and retaining moisture.
有两件重要的事情有助于增强我们的皮肤屏障：神经酰胺和天然保湿因子（NMF）。神经酰胺是我们皮肤中的特殊脂肪，有助于保持皮肤湿润和强韧。它们就像砖墙中的砂浆，将所有东西粘合在一起并保持水分。

NMF comprises different things like amino acids and urea, found in the top stage of our skin cells. It helps hold onto water in the skin, keeping it soft and preventing it from getting dry.
NMF 包含氨基酸和尿素等物质，存在于我们皮肤细胞的上层。它有助于保持皮肤中的水分，使其保持柔软，防止其干燥。

Key Takeaways  核心要点

Epidermal turnover creates and maintains an outer layer on your skin that is tough and acts like a barrier. Factors outside the skin and aging can compromise the barrier. By knowing more about how our skin works, we can take better care of it and keep it healthy for a long time.
表皮更新在皮肤表面形成并维持一层坚韧的屏障。外界因素和衰老会损害这层屏障。通过深入了解皮肤的工作机制，我们可以更好地照顾皮肤，使其长期保持健康。

Reference:  参考文献：

• Wicket, R. R., & Visscher, M. O. (2006). Structure and function of the epidermal barrier. Association for Professionals in Infection Control and Epidemiology, Inc (AJIC), 34(10), S98–S110.
  Wicket, R. R., & Visscher, M. O. (2006). 表皮屏障的结构与功能. 感染控制与流行病学专业人员协会（AJIC），34(10), S98–S110.