Irma

托福閱讀 練習小短文 - 麻醉(醫學學科) 

這兩篇小短文都是與醫學的麻醉有關，第一篇主要在提到有關麻醉如何使人在一段時間內失去知覺；第二篇則是提到一篇新的麻醉相關研究，除了體重之外，病人的腦電波測試可以讓醫生能更精準的給予麻醉劑量這樣的內容。這兩篇來說，托福比較偏愛是類似第一篇這樣的類型，也就是麻醉的原理，這也是經過許多的研究論證而出，也因為麻醉是醫學學科類型，醫學學科的單字只有一個字"長"，所以也就是很喜歡將專有名詞給縮寫，因此在被一些很長的單字時最好可以用字根字首字尾來理解和背單字，比較不容易忘，當然如果可以將內容用畫圖呈現，會記憶的更加深刻。

If you've ever had major surgery, you probably remember lying down and waking up--but nothing in between. Learn about anesthetics on this Moment of Science.      

If you’ve ever had major surgery, you probably remember lying down and waking up–but nothing in between. Thanks to the anesthesiologist, during the actual surgery you were out of it: immobilized and insensitive to pain. But until recently scientists had little understanding of how anesthetics actually work on the cellular level.      

That’s changed thanks to recent experiments performed by researchers at the University of Zurich, in Switzerland. They knew that anesthetics caused pain receptors in the brain to turn off by acting like most drugs do: anesthetizing drugs attach to particular sites on nerve cells and turn them off. The question was, where on nerve cells do these drugs attach?      

Nerve cell membranes(细胞膜) have receptors for different kinds of chemicals produced by the brain. Gamma-amino butyric acid(γ-氨基丁酸), or GABA(伽马氨基丁酸), for example, is a chemical that shuts down nerve cells. The hypothesis was that general anesthesia works by binding to GABA receptors on a nerve cell, thereby activating the receptor and instructing the cell to shut down. So it made sense for the Zurich researchers to focus on GABA receptors.      

To do this they worked with mice that had been genetically engineered to have nerve cells with GABA receptors that wouldn’t respond to anesthetics. And sure enough, when such mice were given anesthetic drugs they weren’t nearly as immune to pain as regular mice that had also been given pain-blocking drugs. Clearly, GABA receptor sites on nerve cells are part of what allows anesthetics to do their job.

At present, a patient's body weight is the main factor in deciding the dose.

But a University of Cambridge study indicated people with high levels of brain connectivity or "chatter" needed a larger dose to put them under.

And this could help doctors work out exactly the amount of anaesthetic a patient requires to become unconscious.

The study, published in PLOS Computational Biology, looked at how the brain's electric signals changed in 20 healthy volunteers given a common anaesthetic called propofol.

They were then asked to press different buttons when they heard different sounds.

After reaching the maximum dose, some were still pressing buttons, while others were unconscious.

The "chatter" or connectivity between areas of the brain was much more pronounced in those who were still conscious.

And when the research team looked at brain activity when the participants were awake, using readings from an electroencephalogram (EEG), they found similar differences.