问题 单项选择题

MS患者在过热或锻炼时可诱发一侧视物模糊、奇痒和肢体无力等症状,是因为()

A.过热和锻炼使患者能量消耗过多

B.失髓鞘的神经纤维的传导对温度的升高极为敏感,是一种温度诱发现象

C.过热和锻炼使患者出汗增多,汗盐刺激所致

D.MS患者存在汗腺的抑制,过热和锻炼时排汗障碍所致

E.以上都不是

答案

参考答案:B

解析:MS具有温度诱发的特点,通过热或是锻炼可诱发一侧视物模糊(Unhoff现象)、奇痒和肢体无力等症状。实验证明失髓鞘神经纤维的传导对温度的升高极为敏感,仅提高0.5℃可阻断某些纤维的传递。说明髓鞘脱失和髓鞘再生区对细微代谢及环境变化极度敏感。吸烟、虚弱和环境温度等可造成神经功能的短暂恶化,有时很易与疾病的复发相混淆,但此时往往不伴有CNS炎症变化的证据。

阅读理解

阅读理解。

     If you go to a fast food restaurant, you will probably see a lot of teenagers. Today, many teenagers are

overweight, and some of this is because of their bad eating habits. Most teenagers love food with a lot of

fat, oil, salt and sugar. People often call this kind of food "junk food".

     But bad eating habits go beyond fast food. We find many teenagers eat unhealthily. Some don't have

breakfast before they go to school. During the day, some don't have a proper meal for lunch. In a recent

survey at one school, scientists found that over two-thirds of the students didn't follow a healthy diet. They

didn't like vegetables, and many of them didn't like to eat fruits. They preferred to eat food with a lot of salt,

sugar or fat.

     Parents today also worry about their children's diet. Some doctors give the following advice: 

    Teenagers shouldn't eat too much junk food.

    Teenagers shouldn't eat food with too much salt. Salt can cause high blood pressure in the future. 

    Teenagers should eat food with less fat, oil and sugar.

    Teenagers need to eat some fruits and vegetables every day. Fruits and vegetables are rich in vitamins and

have little fat.

    Teenagers need to drink more milk. Milk will help their bones grow.

    Teenagers need to eat breakfast every day. This is good for their body and mind.

1. The main reason why many teenagers are overweight is that they eat too much ______. [ ]

A. milk and sugar

B. fruits and sugar

C. vegetables and salt

D. fat, oil, salt and sugar

2. In a recent survey at one school, what did the scientists find? [ ]

A. Teenagers don't have breakfast before going to school.

B. Teenagers have a bad eating habits.

C. Teenagers don't like eating vegetables.

D. Teenagers don't have a proper meal for lunch.

3. Why is milk important to us? [ ]

A. Because it will help the bones to grow.

B. Because it is good for the body and mind.

C. Because it is with less fat, oil and sugar.

D. Because it is junk food.

4. In this passage, doctors advise teenagers to eat more ______. [ ]

A. food with less salt and milk

B. food with much fat and sugar

C. vegetables and fruits

D. food with no salt and oil

5. The best title for this passage should be ______. [ ]

A. Keeping good habits

B. Fast food is good

C. Unhealthy food is bad

D. Advice on healthy eating

单项选择题