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肤色从何而来? – 译学馆
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肤色从何而来?

How We Get Our Skin Color | HHMI BioInteractive Video

[蟋蟀的鸣叫声]
[crickets chirp]
[铙钹的声音]
[cymbal plays]
[铁琴的声音]
[chime plays]
皮肤覆盖我们全身
Skin covers all our bodies,
但是它的颜色因人而异
but its color varies from person to person.
要解释为何如此
To understand why,
我们需要细窥皮肤的分层
we need to peer inside its layers.
[音乐声]
[music plays]
皮肤细胞和它们的伙伴 毛发 汗液和脂腺
Skin cells and their allies–hair, sweat and oil glands
形成身体与外界隔离的第一道防线
form a first line of defense from the environment.
皮肤的三个主要分层
Skin’s three main layers
都是由不同分工的细胞群组成的
are each a distinct community of cells with different jobs.
想要理解什么决定了皮肤的颜色
To see what gives skin its color,
我们需要关注皮肤的最外层
we need to focus on the outermost layer–
表皮
the epidermis
和两类重要的细胞
and two important cell types:
角化细胞和黑素细胞
keratinocytes and melanocytes.
角化细胞是
The keratinocytes are the cells that
形成皮肤表面的细胞
form the surface of the skin
在身体抵抗外界侵害时处在前线
and are on the frontlinefor taking insults from the environment.
在表皮下面
Deeper down in the epidermis,
即 基底层
right at the base of the layer,
我们能找到黑素细胞
we find the melanocytes.
这些星形的细胞
These star-shaped cells
产生重要的色素 黑色素
produce the important pigment melanin.
让我们深入黑素细胞
Let’s zoom inside a melanocyte
来看看它们的运作
to see how this works.
黑色素产生于黑素细胞内部的球状体内
Melanin is produced inside what look like spheres throughout the melanocyte.
这些是黑素体
These are the melanosomes.
黑素体内的化学反应
Chemical reactions inside melanosomes
把一种氨基酸 酪氨酸
turn the amino acid tyrosine
转化为黑色素
into melanin.
两种主要黑色素的不同比例
The proportion of two main forms of melanin
会形成浓黄色和黑褐色
produced a reddish-yellow typeversus a black-brown type;
每个黑素体内的黑色素总量
the total amount of melanin in each melanosome
和表皮中的黑素体的数量
and the number of melanosomes in the epidermis
都是因人而异的
all vary from person to person
从而决定了他们的肤色
and determine their skin color.
黑素体是黑素细胞的黑色素制造工厂
Melanosomes are the melanin factoriesinside melanocytes.
但若要黑色素发挥作用
But for melanin to do its job,
黑素体需要经由黑素细胞长期不断的胞吐
melanosomes need to be transportedto the keratinocytes
被运往角化细胞
via the melanocytes’ long projections.
在角化细胞内
Inside the keratinocytes,
一些黑素体在细胞核周围形成帽状
some melanosomes form a caparound the cell nucleus.
黑素体内的黑色素
The melanin inside the melanosomes
吸收来自日光的紫外线
absorbs the ultraviolet energy from sunlight,
减少直击细胞核的紫外线辐射的数量
reducing the amount of ultraviolet radiation that reaches the nucleus and,
准确来说 直击细胞核内的DNA
in particular, the DNA inside the nucleus.
紫外线会造成基因突变
Ultraviolet radiation can cause mutations in DNA
从而引发癌症
that can lead to cancer.
当紫外线辐射增加
When ultraviolet radiation increases,
黑色素产量会增加
melanin production increases,
因此更多的黑素体被运往角化细胞
and more melanosomes are delivered to keratinocytes.
大多数人能够通过增加黑色素产量变黑
Most people can adjust to greater exposure to the sun
而适应太阳暴晒
by turning up melanin production and tanning.
但是他们的遗传物质
But their genetic inheritance
决定了他们皮肤的基色
determines both the baseline color of their skin
以及它到底能变多黑
and how much it can tan.

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视频概述

皮肤并不只有肉眼可见的一层,而肤色的产生并不简单,角化细胞和黑素细胞都是形成我们肤色的重要参与者。

听录译者

收集自网络

翻译译者

玻璃晴朗

审核员

审核员_AK

视频来源

https://www.youtube.com/watch?v=VC0TL_lYLm8

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