Step1: 听单词讲解音频并跟读，熟悉它们的发音和意思
scr‘utiny 仔细审查v
’hormone 激素n
secr‘ete 分泌v
’rodent 啮齿类动物n
aer‘obic 有氧的a， anaer’obic无氧的
cultured bone cell 培养骨细胞， in culture培养
’regulator调节器n
‘magnitude 幅度n
in terms of 关于
’osteocytes 骨细胞
scler‘ostin 骨硬化蛋白
counterintuitive 反直觉的a
skeletal renovation 骨骼修复
derive from 从...中获取
’dotage 年老n
Step2: 听音频，用简洁的文字回答下面的题目
What can hormone irisin do to human bodies?
What did scintists find about irisin in a lab? (2 points)
What is the fucntion of the sclerostin
What seems to be counterintutive to researchers?
What is the irisin extra value to neuroscience?
Step2: 关注微信公众号“顶萃英语”，回复关键词“高阶22”，可获取参考答案。
This is Scientific Americans, 62nd Science.
I'm Karen Hopkin.
Exercise builds muscle, but it also strengthens bones.
Exactly how exercise boosts bone strength is a matter of debate, and a subject of scientific scrutiny.
Now, a new study in mice shows how a hormone secreted by active muscle cells triggers bone remodeling.
Physical activity stimulates the release of multiple molecules from skeletal muscle.
Take irisin for example.
This hormone, named after the Greek messenger goddess Iris, is produced by running rodents, and by us humans when we do high intensity aerobic training.
Once it's generated, Irisson improves bone density and strength.
To find out how, Bruce Spiegelman and his colleagues that the Dana Farber Cancer Institute and Harvard Medical School took cultured bone cells and located the receptor to which Iris and Binds.
