首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
The immune system is equal in complexity to the combined intricacies of the brain and nervous system. The success of the immune
The immune system is equal in complexity to the combined intricacies of the brain and nervous system. The success of the immune
admin
2019-08-01
70
问题
The immune system is equal in complexity to the combined intricacies of the brain and nervous system. The success of the immune system in defending the body relies on a dynamic regulatory communications network consisting of millions and millions of cells. Organized into sets and subsets, these cells pass information back and forth like clouds of bees swarming around a hive. The result is a sensitive system of checks and balances that produces an immune response that is prompt, appropriate, effective and self-limiting.
At the heart of the immune system is the ability to distinguish between self and non-self. When immune defenders encounter cells or organisms carrying foreign or non-self molecules, the immune troops move quickly to eliminate the invaders. Virtually every body cell carries distinctive molecules that identify it as self. The body’s immune defenses do not normally attack tissues that carry a self marker. Rather, immune cells and other body cells coexist peaceably in a state known as self-tolerance. When a normally functioning immune system attacks a non-self molecule, the system has the ability to remember the specifics of the foreign body. Upon subsequent encounters with the same species of molecules, the immune system reacts accordingly. With the possible exception of antibodies passed during lactation, this so-called immune system memory is not inherited. Despite the occurrence of a virus in your family, your immune system must learn from experience with the many millions of distinctive non-self molecules in the sea of microbes in which we live. Learning necessitates producing the appropriate molecules and cells to match up with and counteract each non-self invader.
Any substance capable of stimulating an immune response is called an antigen. Tissues or cells from another individual (except an identical twin, whose cells carry identical self-markers) act as antigens; because the immune system recognizes transplanted tissues as foreign, it rejects them. The body will even reject nourishing proteins unless they are first broken down by the digestive system into their primary, non-antigenic building blocks. An antigen announces its foreignness by means of intricate and characteristic shapes called epitopes, which stick out from its surface. Most antigens, even the simplest microbes, carry several different kinds of epitopes on their surface, some may even carry several hundred. Some epitopes will be more effective than others at stimulating an immune response. Only in abnormal situations does the immune system wrongly identify self as non-self and execute a misdirected immune attack. The result can be so-called autoimmune disease. The painful side effects of these diseases are caused by a person’s immune system actually attacking itself.
The remembering power of a person’s immune system is______.
选项
A、mostly descended from his/her ancestors
B、partially passed down from his/her mother
C、mainly acquired through fighting against foreign cells
D、basically generated by its communications network
答案
C
解析
细节题。第二段第六句以下内容谈到ability to remember(记忆能力)。第八句明确指出,除哺乳期内可能传递部分抗体外,其他记忆能力需免疫系统自身学习获得,第九句举例说明这一现象,[A]中的is descended(是遗传下来的)与第八句的is not inherited(不是遗传而得的)相矛盾;[B]中的passed down与[A]相同;[D]说法中文中并无依据。只有[C]与第九句意思相符,为正确选项。
转载请注明原文地址:https://kaotiyun.com/show/hI2Z777K
0
考研英语一
相关试题推荐
Ifcomfortablyoutpacingyourrivalsisthemainmeasureofautomotiveachievement,Tesla’selectriccarisaresoundingsuccess
Ifcomfortablyoutpacingyourrivalsisthemainmeasureofautomotiveachievement,Tesla’selectriccarisaresoundingsuccess
Wheneducationfailstokeeppacewithtechnology,theresultisinequality.Withouttheskillstostayusefulasinnovationsar
AsthecountrywiththeEuropeanUnion’sfastestageingpopulation,Germanyhasrepeatedlyadjusteditspensionsystemtoavert
AsthecountrywiththeEuropeanUnion’sfastestageingpopulation,Germanyhasrepeatedlyadjusteditspensionsystemtoavert
Britain’sprivateschoolsareoneofitsmostsuccessfulexports.Thechildrenofthewell-heeledflocktothem,whetherfromCh
Anysufficientlyadvancedtechnology,notedArthurC.Clarke,aBritishscience-fictionwriter,isindistinguishablefrommagic.
Thecountry’sinadequatementalhealthsystemgetsthemostattentionafterinstancesofmassviolencethatthenationhasseen
Thecountry’sinadequatementalhealthsystemgetsthemostattentionafterinstancesofmassviolencethatthenationhasseen
随机试题
下列关于药物治疗作用的叙述,正确的是
可以从事除公司上市、企业清算以外房地产估价业务的房地产机构属于()。
在设备安装工程中,具备单机无负荷试车条件的,应当由( )组织试车。
由少数几家企业控制的市场结构是()。
简述《教师法》中规定的教师应承担的义务。(北京)
一块冰在沙里被融化到很小,它抱怨说:“要是在南极就好了,就不会被融化了。”沙听了后对它说:“沙漠里缺少冰,你在沙漠里是非常珍贵的,南极的冰很多。你到那里就失去了价值。”请结合自身谈谈这个故事对你的启示。
运用法治思维,就要_________权利平等、公平正义等法治理念以及由此决定的法律思维方式,去思考和评判一切涉法性社会争议问题。法律必须被信仰,否则将形同虚设。如果执政党的各级组织及其领导成员自己都不能深深地信仰并服从在党的领导下制定的宪法和法律,法治建设
ThestatisticsI’vecitedandthelivingexamplesarealltoofamiliartoyou.Butwhatmaynotbesofamiliarwillbetheincre
基于ARM内核的嵌入式芯片中包含互连通信组件,下面列出的()不属于互连通信组件?
Heisnotintheoffice.Hemusthavegonetohaveclasses,______?
最新回复
(
0
)