Smooth muscle along the trachea and the first few branches of bronchi have beta 2 adrenergic receptors.

和初级支分支的平滑肌上，都有β2受。

Going back to that turkey, when you're running, the sympathetic nerves stimulate those beta 2 adrenergic receptors and increase the diameter of the airways.

再来看逃离大鹅的例子：当我们在奔跑时，交感神经系统激动β2受，使道扩张，以吸入更多氧。

Class 2 beta blockers These drugs bind to beta-1 adrenergic receptors and block the sympathetic influences that act through these receptors.

第二类是β受阻滞剂。这类药物与β-1肾上腺素能受结合，阻断交感神经这些受产生的影响。

Also, medications might be given, to help reduce pain, reduce stone formation, like potassium citrate, and to help stones pass through, like alpha adrenergic blockers and calcium channel blockers.

亦可通过给药（如柠檬酸钾）来减轻疼痛，减少结石生成；以及肾上腺素能α受阻断剂以及钙离子通道阻断剂，促进结石排出。