into the tissue that it serves

它服务的组织中去
so it doesn't have a lot of oxygen anymore.

静脉血中不再含有丰富的氧气
It has a lot of waste products now,

而是带有较多的废物
the waste products that are generated by these tissues during metabolism.

这些代谢废物来自于组织的新陈代谢
It has a lot of carbon dioxide

静脉血中含有较多二氧化碳
which is the end product of glucose metabolism,

这是糖代谢的末端产物
it has acids that are generated from metabolism,

还有代谢过程产生的酸
it has the end products of nitrogen metabolism,

也包括氮代谢的末端产物
which is chiefly urea and ammonia,

主要是尿素和氨
and that blood is indicated here as a blue line.

静脉血在这里用蓝线表示
Now, we usually show these blue colored vessels,

我们通常用蓝色表示静脉
usually show them as red and blue,

通常分别用红色和蓝色表示血液