If we are hiking on the top of a snowy mountain, the rising demand for oxygen from our body is met as soon as our kidney responds by secreting a type of hormone into the blood.

如果我们在雪山的山顶上徒步旅行，当我们的肾脏通过向血液中分泌一种激素而做出反应时，我们身体对氧气不断增加的需求就会得到满足。