英语听力文摘 English Digest 314、手茧如何形成？
时间：2019-02-24 作者：英语课 分类：英语听力文摘 English Digest
What Are Calluses And How Are They Formed?
皮肤上的茧是如何形成的？
人体皮肤由于劳动过程长期摩擦造成皮肤表皮细胞坏死而形成的，主要出现于手掌、足掌等部位。长时间的受到磨檫,组织细胞的老死,角质层的严重受损形成手茧．
Most of us are familiar with calluses.
These extra-tough patches of skin are generally quite useful–we might even say handy–because they act like a kind of natural armor, protecting areas of skin that get an unusual amount of wear and tear. Have you ever wondered exactly what a callus is, or how it forms on your skin?
Callus formation is triggered by pressure or abrasion 1. The heel of your foot as it rubs inside your shoe, or the palm of your hand if you’re doing a lot of manual labor 2 are good examples of this.
While it might feel like a callus is something extra, added to your skin, it’s actually just a build-up of what’s already there.
Here’s How It Works
Your skin has a number of layers of different types of cells.
The outermost 3 is a layer of hardened, dead cells. This top layer is usually about twenty-five cells thick, and it constantly replaces itself as the outermost cells flake 4 off to be replaced by new hardened, dead cells underneath 5.
All About Friction 6
If your skin is subject to an unusual amount of friction, this layer of dead cells increases. New dead cells are added faster than the old ones slough 7 away. This can build up the outer layer from twenty-five cells thick to over a hundred cells thick. You’ve grown a callus.
While calluses are generally useful, if the process continues unchecked a callus can thicken into a cone-shaped structure called a corn. These super calluses can be quite painful, and may require the attention of a doctor.
译文
对于“老茧”，我们都很熟悉。
这些皮肤上突出的硬皮是很有用的，也可以说是方便，因为他们扮演着保护常磨损皮肤的天然盔甲的角色。你是否思考过什么是老茧？他又是怎样形成的？
老茧是由压力和摩擦而形成。脚后跟的茧是由其在鞋里摩擦而形成，正如手茧是在大量的劳动过程中形成。
尽管看起来似乎是皮肤上多出的部分，然而事实是已经存在的皮肤角质的累积。
形成过程
皮肤是由若干层不同类型的皮肤构成。
表层是一些坏死的硬细胞，通常有25个细胞那么厚，表层细胞不断的脱落，取而代之的是下层硬的坏死细胞，由此而完成自我更替过程。
一切皆由摩擦引起
假如皮肤受到不寻常量的摩擦，这层坏死细胞将会增加，新的坏死细胞增长速度比旧细胞脱落的速度快，这就致使皮肤表层的厚度增加到100个细胞那么厚，由此，老茧便形成。
虽然一般来讲，茧是有益的，但如不控制其过程，老茧厚度就会增加到被称作鸡眼的锥形结构，那样就会很疼，甚至需要去看医生。
- Diamonds have extreme resistance to abrasion.钻石极抗磨损。
- This analysis is helpful to the research of derailment and abrasion machenism.该分析有助于脱轨和磨耗机理的探讨。
- We are never late in satisfying him for his labor.我们从不延误付给他劳动报酬。
- He was completely spent after two weeks of hard labor.艰苦劳动两周后，他已经疲惫不堪了。
- He fired and hit the outermost ring of the target.他开枪射中了靶子的最外一环。
- The outermost electron is shielded from the nucleus.原子核对最外层电子的作用受到屏蔽。
- Drain the salmon,discard the skin,crush the bones and flake the salmon with a fork.将鲑鱼沥干，去表皮，粉碎鱼骨并用餐叉子将鱼肉切成小薄片状。
- The paint's beginning to flake.油漆开始剥落了。
- Working underneath the car is always a messy job.在汽车底下工作是件脏活。
- She wore a coat with a dress underneath.她穿着一件大衣，里面套着一条连衣裙。
- When Joan returned to work,the friction between them increased.琼回来工作后，他们之间的摩擦加剧了。
- Friction acts on moving bodies and brings them to a stop.摩擦力作用于运动着的物体，并使其停止。