英语听力文摘 English Digest 446、有三个心脏的家伙！

You Gotta Have Hearts

      你必须得有的心脏

       When it comes to weird sea-creatures, octopuses are hard to beat. There’s the well-known ink-squirting defense 1 system, the bird-like beak, and the eight tentacles with their double rows of suckers.

       What’s less well known is that octopuses have more than one heart. They have three, to be exact, each one crucial to maintaining the robust blood pressure that allows octopuses to be active hunters and powerful swimmers.

       Human hearts have two main jobs. One is to pump blood to the lungs, where it dumps carbon dioxide and picks up oxygen. The second is to distribute freshly oxygenated blood to the rest of the body.

       Making sure enough blood gets to the lungs is so important, in fact, that two of the human heart’s four chambers 2 are reserved solely 3 for that task.

       Octopus hearts solve the circulation 4 problem a bit differently. They have one main heart, called the systemic heart, and two smaller hearts located near their gills. The two smaller hearts perform the same task as the right side of the human heart.

       They pump blood to the gills where it dumps waste and loads up on oxygen, then pump the oxygen-rich blood back to the main heart. The main heart then pumps the refreshed blood through the octopus’s body.

       Besides having three hearts, the octopus circulatory system differs from the human system in one other way. Human blood contains the protein hemoglobin, which helps it absorb oxygen and causes its red color. The blood coursing through the three hearts of the octopus is blue, thanks to a different protein called hemocyanin.

       Octopuses are rather shy, so despite their blue blood they are not exactly kings of the sea. But there’s no denying that they’ve got a lot of heart.

       说到怪异的海洋生物，那就的非章鱼莫属了。因为他们有闻名的喷墨防御系统，有像鸟儿一样的嘴巴，以及八条带着两行吸盘的触角。

       （然而）没那个为人所知晓的是，章鱼不只有一个心脏。确切的说，它们有三个！每一个对于章鱼拥有强健的血压都至关重要，因为它们能让章鱼成为敏捷的猎手，成为游泳健将。

       人类的心脏有两大功能。一是将血泵到肺中（肺是排除二氧化碳，吸收氧气的地方）；二则是将新鲜的含有氧气的血液传输到身体的其它部位。

       事实上，确保有足够的血进入肺部是很重要的，而这个任务是由人类心脏的4个腔中有两个来单独完成的。

       章鱼的心脏解决这个（血液）循环问题就有点不一样了。它们有一个主心脏叫系统心脏，还有两个心脏要小点且位于腮附近。这两个小点的心脏（的功能）就跟人心脏的右边部分功能是一样的。

       它们将血泵到排除废物收集二氧化碳的腮里，在将含有丰富氧气的血液泵回到主心脏。主心脏接着就会将焕然一新的血液泵到章鱼的身体。

       除了有三个心脏外，章鱼的循环系统在另一方面也和人类的不一样。人类的血液含有含蛋白质的血红蛋白，它会帮助吸收氧气，并使血液呈红色。血液流经章鱼的三个心脏就成了蓝色，这多亏了一种叫血蓝蛋白的蛋白质。

       章鱼是很害羞的，所以尽管它们有蓝色血液，却并不能使之成为真正的海洋之王。但毫无疑问它们是“太有心”了！

       Vocabularies and expressions：

       squirt：喷射

       loads up on：大量储存

       circulatory system ：循环系统