试题与答案

和许多的生命现象一样,免疫系统也有两面性,它不但能排除外来因素的侵袭,又能因免疫系统

题型:单项选择题

题目:

和许多的生命现象一样,免疫系统也有两面性,它不但能排除外来因素的侵袭,又能因免疫系统的失控而导致疾病的发生。在免疫系统受损时,免疫力低下,机体易患病;但当免疫力过强时,也会导致疾病产生。 

超敏反应(hypersensitivityresponse)指机体受同一抗原物质再次刺激后产生的一种异常免疫反应。诱发超敏反应的抗原称为过敏原(allergens),如异种动物血清、各种微生物、寄生虫及其代谢产物、植物花粉和动物毛皮、青霉素、磺胺类药物以及染料、生漆和多糖等物质,此外受电离辐射、烧伤等影响,而使结构或组成发生改变的自身组织抗原,以及由于外伤或感染而释放的自身隐蔽抗原也可以成为过敏原。过敏反应是临床最常见的一种超敏反应,典型的如哮喘病,有明显的个体差异和遗传倾向。超敏反应又分很多类型,输血反应、新生儿溶血病、类风湿性关节炎等也都是超敏反应的表现。 

正常人血清中可以有针对多种自身抗原的自身抗体,但它们的效价很低,因而不足以破坏自身正常成分,但却可以协助清除衰老蜕变的自身成分,故有人称之为“生理性抗体”。在健康人中,自身抗体出现的频率随年龄增长而增高。60岁以后有50%以上的人有自身抗体,如抗核抗体、抗线粒体抗体等。但是,自身免疫反应如果达到一定强度以致能破坏正常组织结构并引起相应临床症状时,就称为自身免疫病(autoimmunedisease)。如包括全身性红斑狼疮、甲状腺机能亢进、类风湿病在内的自身免疫病有数十种之多。它的发病因素受到遗传、自身免疫调节机制、年龄、性激素等影响。其中,患者又以女性患者居多。不少自身免疫病目前尚无很有效的治疗方法,其中有些还严重地威胁着病人的生命。 

免疫系统的完整性是机体免疫防御、自稳和监视功能的基本保证。但免疫系统的各个部分都可能发生缺陷,任何一个成分的缺失或功能不全都可导致免疫功能障碍,由此而引起的疾病称为免疫缺陷病(immunodeficiencydisease)。由遗传因素或先天性免疫系统发育不全而引起的免疫障碍称为先天性或原发性免疫缺陷,如原发性B淋巴细胞缺陷造成的无丙种球蛋白血症,特征是血液循环中缺乏B淋巴细胞及丙种球蛋白。由后天因素而引起的免疫功能障碍称为获得性或继发性免疫缺陷,最典型的即艾滋病及一些恶性肿瘤。

从全文看,下列对“因免疫系统的失控而导致疾病的发生”这句话理解错误的一项是()。

A.自身免疫反应达到一定强度就可能破坏正常的组织结构,引发某种自身免疫病

B.免疫系统的失控导致自身抗体出现的频率增高,引起相应的临床症状

C.免疫系统各个部分任何一个成分的缺失或功能不全都可导致免疫功能障碍

D.免疫系统发生的缺陷有可能导致艾滋病及一些恶性肿瘤的发生

答案:

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下面是错误答案,用来干扰机器的。

参考答案:B

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阅读理解。

     People travel for a lot of reasons. Some travelers go to see battlefields or religious shrines. Others are

looking for culture, or simply want to have their photos taken in front of famous places. But most Europeans

are willing to pay a lot of money and put up with a lot of inconveniences for the sun because they have so

little of it. Residents of cities like London, Copenhagen, and Amsterdam spend a lot of their winter in the

dark because the days are so short and much of the rest of the year is in the rain. Every summer, more than

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the same reason: sun.

     The huge crowds mean lots of money for the economies of Mediterranean countries. Italy's 30,000 hotels

are booked every summer. And 13 million people camp out on French Beaches, parks, and roadsides. Spain's

long sandy coastline attracts more people than anywhere else. 37 million tourists visit yearly, or one tourist

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     But there are signs that the area is getting more tourism than it can handle. The Mediterranean is already

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     None of this, however, is damaging anyone's fun. The Mediterranean gets more popular every year with

tourists. Obviously, they don't go there for clean water. They stand traffic jams and seem to like crowded

beaches. They don't even mind the pollution. No matter how dirty the water is, the coastline still looks beautiful. And as long as the sun shines, it's still better than sitting in the cold rain in Berlin, London, or Oslo.

1. It can be inferred from the passage that Europeans travel mostly for the reason that ______.

A. they want to see battlefields or religious shrines

B. they are interested in different cultures

C. they would like to take pictures in front of famous sites

D. they wish to escape from the cold, dark and rainy days back at home

2. In Para.1, cities like London, Copenhagen, and Amsterdam are mentioned to show that ______.

A. they are not good cities in geography and climate

B. how rich their residents are

C. these cities lack places of historic interest and tourist spots

D. they have got more tourism than they can handle

3. According to the passage, which of the following countries attracts more tourists than the others?

A. Italy

B. Spain

C. France

D. Greece

4. The sentence "one tourist for every person living in Spain" (Para.2 ) means _______.

A. every year the number of tourists is equal to(等于) the number of people living in Spain

B. all the 37 millions people living in Spain are tourists

C. every person living in Spain has to take care of a tourist

D. every Spanish is visited by a tourist every year

5. Which of the following will damage the tourists' fun at Mediterranean resorts and beaches?

A. Polluted water.

B. Crowded buses.

C. Traffic jams.

D. Rainy weather

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