【英语时差8,16】骨质疏松-上

Today’s word is: osteoporosis! Yep, osteoporosis. Now, you’ve heard this word before, and you know it has something to do with bones. But can you actually explain what it is? The answer is straight-forward. It comes down to the fact that we human beings need calcium¹ in our blood–it allows us to do all sorts of neat things, from contracting muscles to conducting nerve impulses. Where to get some calcium? Food is a good idea. But what if there isn’t always calcium-rich food to be had, as was probably the case for most of our long evolutionary² history? Best to store some for a rainy day. Store it where? The skeleton works! Then, when the blood runs low on calcium, a signaling device called the parathyroid gland³ can activate⁴ a process by which calcium is taken from the skeleton and put back into the blood.

1 calcium   

n.钙(化学符号Ca)

参考例句：

• We need calcium to make bones.我们需要钙来壮骨。
• Calcium is found most abundantly in milk.奶含钙最丰富。

2 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

3 gland   

n.腺体，(机)密封压盖，填料盖

参考例句：

• This is a snake's poison gland.这就是蛇的毒腺。
• Her mother has an underactive adrenal gland.她的母亲肾上腺机能不全。

4 activate   

vt.使活动起来，使开始起作用

参考例句：

• We must activate the youth to study.我们要激励青年去学习。
• These push buttons can activate the elevator.这些按钮能启动电梯。