人体的三道防线
这是校长陪伴你的第5天 | 第005期
彭敬慈博士
海嘉国际双语学校总校长
海嘉教育研究院院长
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校长之音005期——彭博士.mp3 来自海嘉国际双语学校BIBA 00:00 03:25 Dr. Pang Day5-EN.mp3 来自海嘉国际双语学校BIBA 00:00 03:21 Please refer to the text below:
各位同学大家好！
昨天学完病毒以后，今天我们再学学人体的免疫系统，看看人体是如何防御病菌的。
病菌(Pathogens)是一些微生物，包括细菌（Bacteria）、病毒（Viruses)与真菌(Fungi) 等等。
人体有三道防线去防御它们。第一道，主要是我们全身的皮肤及一些外面的化学分泌物，例如是眼泪，防止它们进入身体。
第二道，主要是皮肤下面的白血球，当受伤时候，把进入的病菌尽快杀掉。
第三道，主要是血液及淋巴液内的白血球。当进入人体内的病菌数目太多而第二度防线都不够去杀掉他们时，病菌便会进入血液及淋巴液，血液及淋巴液内的白血球会产生免疫反应，把所有病菌段掉。
第三道防线是很强烈的，所以一般来说都可以把入侵的病菌杀掉，帮助我们康复。但是如果第三道防线都不够力量去清除病菌的时候，我们便要依靠药物去帮助。一般来说药物都可以帮助我们，把所有病菌杀死，帮助我们复原。
但是有些病菌的杀伤力很大，例如现在的冠状病毒，同时我们还没有药物或疫苗的时候，第三道防线都不足够，我们便会有生命的危险了。这时，反过来说最好的方法，其实就是加强我们的第一道防线，不容许它们进入体内。所以现在的冠状病毒，因为它是依靠空气传染的，所以暂时最好的防御方法，就是带口罩，加强第一道防线，尽量不容许它进入我们的身体里面。
希望从上次病毒是「非生物」的概念，及这一次第三道防线也不足够去抵挡冠状病毒的概念（事实），大家（能）更加明白戴口罩的重要性。
好，明天我们再说说有什么方法，可以提升我们的免疫力，加强预防。明天见！
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Dr. Pang Day5-EN.mp3 来自海嘉国际双语学校BIBA 00:00 03:21
Dear students,
After learning about viruses, today we are going to learn about the body’s immune system, learning how do we fight against pathogens.
Pathogens are micro-organisms, including bacteria, viruses and fungi etc.
The body has three lines of defence to protect ourselves from pathogens. The first line of defence is mainly the skin covering the whole body and some chemical secretions such as tears, to prevent pathogens from entering the body.
The second line is mainly the white blood cells under the skin. They will kill the pathogens when the skin is cut.
The third line is mainly the white blood cells in the blood and lymph. When too many pathogens have entered the body and the second line cannot kill them all, some will get into the blood or lymph.
The white blood cells there will initiate immune responses to kill the pathogens.
The third line is very strong, and usually can kill most pathogens, and help us recover. However, in some situations when the third line is not strong enough, we will need to take medicine to help us kill the pathogens. Normally medicine can kill them and help us recover.
Nevertheless, for pathogens which are very strong and when there is no medicine yet, such as in the case of the present Corona virus, we will be in a dangerous position. In these cases, the best method indeed is to strengthen our first line of defence, and do not let the pathogen gets into our body. Thus, as Corona viruses is spread by air, the best method of prevention is to wear a mask to cover our nose and mouth to strengthen our first line of defence, and do not let them enter the body as much as possible.
Hope from the knowledge that viruses are non-living as we discussed last time, and that even the third line of defence is not strong enough to kill corona viruses, you now understand better why wearing a mask is so important!
Good, tomorrow we will learn about ways to enhance our immunity, to get us better protected! See you tomorrow!
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