托福与 听力加试 神经元细胞GLIAL CELL.doc

托福机经听力加试神经元细胞GLIAL CELL原文及试题答案 GLIAL CELL Glial cells, commonly called neuroglia or simply glia (greek for glue; researches originally believed that glial cells served as the putty that held the neurons together, recent research indicates that these cells provide very important contributions.), are non-neuronal cells. In the human brain, glia are estimated to outnumber neurons by about 10 to 1. Glial cells provide support and protection for neurons, the other main type of cell in the central nervous system. The four main functions of glial cells are to surround neurons and hold them in place, to supply nutrients and oxygen to neurons, to insulate one neuron from another, and to destroy pathogens and remove dead neurons. Traditionally glia had been thought to lack certain features of neurons. For example, glia were not believed to have chemical neurotransmitters. They were considered to be the passive bystanders of neural transmission. However, recent studies disproved this. It is inappropriate nowadays to consider glia as glue in the nervous system as the name implies but more of a partner to neurons. They are also crucial in the development of the nervous system. 中文背景: Listen to a lecture in a biology class. 好，在今天开始讲课之前，我们先review一下上节课的内容。上节课，我们讲了神经元细胞（计算机屏幕：Neutron）, 以及其工作的原理（function），有谁能回忆起来？ Male student, Bernard：Neutron是指在大脑运作的过程中起作用的一种细胞cell，它接受electronic signal，经过传递，然后再送往大脑的接收器 receptor。” Female Professor忽然打断（重听题）：“好的。 Bernard，可以了。你的答案很complete。” 那么今天，我们来讲一下glial cell（字会出现在计算机屏幕），这也是大脑物质中的一种。 历史上Historically，生物学家不重视glial cell，对神经传导的研究仅限于neuron（神经元），也叫nerve cell。神经传导通过electrical communication从一个结点传到另一个结点，神经元被认为起主要作用，glial cell研究的很少，一直被忽略，被看作help the growth of neurons（有题），起辅助作用（support neutron），例如，protect、repair the damaged neutron cell。 后来，偶然发现大脑中glial cell比neuron的数目多很多，glial cell引起了科学家的重视，开始研究它究竟起什么作用（有题，问glial cell怎么引起科学家注意的）。 人们发现胶质细胞也有传导信息的作用，不过不是通过生物电(not electronically communication)，而是化学物质传导(but chemical communication)（有题）。传统观点一直误以为glial cell也像nerve cel