【英语时差8,16】肉毒杆菌毒素(在线收听

 
In our beauty conscious culture, people will go to great lengths to improve their appearance. Liposuction, tummy tucks, silicone implants--it's all been done. But surely we wouldn't resort to injecting ourselves with a toxic substance that causes botulism, would we? Of course we would, in the form of Botox injections, widely advertised as a quick, easy way to remove wrinkles and crow's-feet.   
Botox is the marketing name given to a neurotoxin called botulinum toxin A. This toxin comes from the bacterium that produces the poisons responsible for causing botulism. Botulism is a form of food poisoning, the most serious symptom of which is paralysis. Botulism-related toxins attach to nerve endings, where they block their ability to trigger muscle contractions. If muscles can't contract, they can't move, resulting in paralysis.
 
So why would anyone risk injecting Botox into his or her body? There are legitimate medical reasons, such as treating spasms and involuntary muscle contractions. Although the paralyzing effects are not permanent, they can last up to eight months. And as long as Botox is injected directly into a particular muscle group, there's little chance that it will spread to other parts of the body.
 
As a beauty treatment, Botox does what it's meant to do: paralyze muscles. For example, injecting botox into muscle groups near the eyes will temporarily paralyze those muscles, keeping them from scrunching up. Consequently the wrinkles, or crow's feet, they cause temporarily disappear. In time, however, wrinkles reappear. Not even Botox can permanently reverse the march of time.   
  原文地址:http://www.tingroom.com/lesson/englishtimeover/341925.html