听力文摘：为什么昆虫的血是绿色的或是黄色的?（在线收听）

You've probably heard someone use the phrase “blood red,”but have you ever wondered if all blood really is red?

你可能听到有些人这样说“血红色”，但是你是否想过是不是所有的血都是红色的？

For example, think about the bugs you'veseen splatter against your car's windshield, leaving behind a clear, yellowish, or greenish liquid. Thatliquid, is hemolymph, or insect blood.

举个例子，想一想你所见过的臭虫撞到你汽车的挡风玻璃上时，留下一滩清楚的，黄色或是绿色的液体。这种液体是昆虫的淋巴液，或许是昆虫的血。

The blood of an insect functions differently than the blood of a human.

昆虫血和人类的血在功能上大不相同。

In humans, blood gets itsred color from hemoglobin, which travels through blood vessels carrying oxygen from the lungsto the rest of the body.

对人类来说，血液之所以呈现红色是因为有血红蛋白，血红蛋白通过血管从肺部向全身各处运输氧气。

Insect blood, however, does not carry gasses and has no hemoglobin.

而对于昆虫来说，血液既不会运输任何气体，也没有血红蛋白，

Instead, bugs have a system of tubes that transport gasses directly between their cells and theoutside air.

相反地，昆虫的身体中有一个管路系统，可以直接在细胞核外界空气中进行气体运输。

In fact, insects don't even have blood vessels. Instead there is a hollow space inside their externalskeleton in which their blood oozes around.

事实上，昆虫甚至没有血管，取而代之的是外骨架内部的空洞，血液可以在周围渗出。

This cavity extends to the antennas, legs, and wingveins.

这种腔体结构延伸至触角，腿和翅膀。

The bug's heart, a long tube that stretches the length of its body, pushes the blood fromthe rear end of the insect on forward.

昆虫的心脏，一条绵延整个身体的长管子，将血液从身体的末端推到前面。

The bug may also have little hearts at the ends of itsextremities to help move the blood along.

昆虫在四肢处也可能有少许心脏来帮助血液流动。

Pumping blood is a slow process: it takes about eight minutes for an insect's blood to circulatecompletely.

泵血是一个缓慢的过程：昆虫全身血液完全循环一次大约需要八分钟。

Like human blood, bug blood carries nutrients and hormones to the insect's cells.

类似于人类血液，昆虫血液运载营养和激素到昆虫细胞中。

Thegreenish or yellowish color of insect blood comes from the pigments of the plants the bug eats.

昆虫血液中的绿色或者黄色来自于昆虫吃的植物的色素。