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伤口是怎样自我修复的 – 译学馆
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伤口是怎样自我修复的

How a wound heals itself - Sarthak Sinha

你身体中最大的器官并非肝脏
The largest organ in your body isn’t your liver or your brain.
也不是大脑 而是皮肤
It’s your skin,
一个成年人的皮肤展开面积约为1.86平方米
with a surface area of about 20 square feet in adults.
虽然人体不同部位的皮肤有着不同的特征
Though different areas of the skinhave different characteristics,
但绝大多数都承担着相似的功能
much of this surface performssimilar functions,
比如排汗、感受冷热以及生长毛发等
such as sweating, feeling heat and cold,and growing hair.
当皮肤被深度切伤或创伤时
But after a deep cut or wound,
新愈合的部分看上去总会有别于周围皮肤
the newly healed skin will look different from the surrounding area,
并且可能在短期内 或者永久性地失去部分
and may not fully regain all its abilities for a while,
功能
or at all.
要究其原因
To understand why this happens,
我们先来看看人体皮肤的结构
we need to look at the structure of the human skin.
皮肤最外面的一层叫做表皮
The top layer, called the epidermis,
主要由一些硬化细胞组成 叫做角化细胞
consists mostly of hardened cells, called keratinocytes,
能够提供保护作用
and provides protection.
由于表皮本身会经常性地脱落与再生
Since its outer layer is constantly beingshed and renewed,
要修复它也较为容易
it’s pretty easy to repair.
但有时候 一些创口伤及真皮层
But sometimes a wound penetratesinto the dermis,
而真皮层中含有的血管、多种腺体和神经末梢
which contains blood vesselsand the various glands and nerve endings
是皮肤多种功能的保障
that enable the skin’s many functions.
当深度伤口产生时 皮肤将进入由四个相互重叠的
And when that happens, it triggers thefour overlapping stages
阶段构成的再生过程
of the regenerative process.
第一阶段凝血
The first stage, hemostasis,
是皮肤在应对以下威胁:
is the skin’s response to two immediate threats:
你正在失血 并且表皮层的物理
that you’re now losing blood and that the physical barrier
屏障已被攻破
of the epidermis has been compromised.
为减少出血 血管发生紧缩
As the blood vessels tighten to minimizethe bleeding,
这一过程叫做血管收缩 产生的血凝块
in a process known asvasoconstriction,
能够帮助消除皮肤遭受的两大威胁
both threats are averted by forminga blood clot.
此外 一种叫做血纤维蛋白的特殊蛋白质
A special protein known as fibrin forms cross-links
在皮肤表面形成交叉网状结构
on the top of the skin,
以防止血液的流出和细菌病菌的侵入
preventing blood from flowing out and bacteria or pathogens from getting in.
第一阶段持续大约三小时后
After about three hours of this,
皮肤开始变红
the skin begins to turn red,
这意味着第二阶段的到来 即炎症反应阶段
signaling the next stage, inflammation.
此时失血已得到控制 保护屏障也已形成
With bleeding under controland the barrier secured,
人体开始派出特殊的细胞抵抗可能已经入侵的病菌
the body sends special cells to fight any pathogens that may have gotten through.
这些细胞中最重要的就是白细胞
Among the most important of theseare white blood cells,
也被称作巨噬细胞
known as macrophages,
除了产生生长因子加速愈合
which devour bacteria and damage tissue
它们还能够吞噬细菌和损伤的组织
through a process known as phagocytosis,
这一吞噬的过程叫做吞噬作用
in addition to producing growth factorsto spur healing.
因为这些体型微小的战士
And because these tiny soldiersneed to travel
需要通过血液到达伤口
through the blood toget to the wound site,
之前收缩的血管此时将发生扩张
the previously constrictedblood vessels now expand
这一过程叫做血管舒张
in a process called vasodilation.
大约在受伤后的两到三天
About two to three days after the wound,
成纤维细胞开始进入伤口 意味着第三阶段——增殖阶段的到来
the proliferative stage occurs, when fibroblast cells begin to enter the wound.
在胶原沉积的过程中
In the process of collagen deposition,
成纤维细胞能在伤口处产生一种纤维状的蛋白质 名为胶原蛋白
they produce a fibrous proteincalled collagen in the wound site,
它能形成皮肤结缔组织 以取代之前的血纤维蛋白
forming connective skin tissueto replace the fibrin from before.
当表皮细胞分裂重新形成外保护层
As epidermal cells divide to reformthe outer layer of skin,
真皮层也在收缩以闭合伤口
the dermis contracts to close the wound. Finally,
最后一个阶段是组织重组阶段
in the fourth stageof remodeling,
随着新沉积的
the wound matures
胶原蛋白重组和转化为特定的形态
as the newly deposited collagen is rearranged and converted
伤口变得成熟
into specific types.
这一过程可能会持续一年以上
Through this process,which can take over a year,
随后新生皮肤的伸缩强度就会得到提高
the tensile strength of the new skinis improved,
血管和其它连接组织也得到增强
and blood vessels and other connectionsare strengthened.
随着时间的推移 依据伤口的严重程度
With time, the new tissuecan reach from 50-80%
以及皮肤原先功能的好坏
of some of its original healthy function,
新生组织能够恢复到原先五成到八成的功能
depending on the severity of the initial wound and on the function itself.
但是因为皮肤并没有完全复原
But because the skindoes not fully recover,
疤痕仍是全世界医生主要关注的临床问题
scarring continues to be a major clinical issue for doctors around the world.
虽然通过研究 人们对皮肤伤口愈合的过程
And even though researchers have madesignificant strides
有了更深入的认识
in understanding the healing process,
但许多重要谜团仍未解开
many fundamental mysteriesremain unresolved.
比如 成纤维细胞到底来自血管
For instance, do fibroblast cells arrivefrom the blood vessels
还是来自伤口周围的皮肤组织?
or from skin tissue adjacent to the wound?
又比如 为什么诸如鹿之类的其它哺乳动物
And why do some other mammals,such as deer,
相比人类能够更有效更彻底地修复它们的伤口?
heal their wounds much more efficientlyand completely than humans?
通过寻求此类问题的答案
By finding the answers to these questionsand others,
人类也许有一天能有足够的修复能力
we may one day be able to heal ourselves so well
那时疤痕困扰也将成为
that scars will be just a memory.

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