问题 问答题

设计实验证明迷走神经对家兔呼吸运动的调节作用。

答案

参考答案:(1)方法与步骤
①家兔麻醉后,背位固定在手术台上,术部剪毛、消毒。
②分离颈部两侧迷走神经,在神经下方穿线备用。
③分离气管并安置插管,将气管插管与呼吸换能器相连,用信号记录设备记录由呼吸换能器所得的信号,从记录的曲线反映动物的呼吸运动状态。
④描记动物正常呼吸运动曲线。
⑤结扎并切断一侧迷走神经,观察、记录呼吸运动的变化。
⑥剪断另一侧迷走神经,记录呼吸运动曲线的变化。
(2)结果预测及分析
①切断一侧迷走神经后,动物的呼吸变深、变慢。从记录的呼吸运动曲线可以看到,与正常曲线相比,神经被切断后的曲线幅度加大、频率减慢。
②切断另一侧迷走神经后,动物的呼吸变得更深、更慢。从记录的呼吸运动曲线可以看到,与切断一侧迷走神经后的曲线相比,曲线幅度又有加大、频率又有减慢。
③实验结果表明,切断迷走神经,会使动物的呼吸运动发生变化,吸气与呼气之间的交替变慢,呼吸频率减慢。实验说明迷走神经可以调节呼吸节律。
正常生理状况吸气时肺扩张,牵拉呼吸道使之扩张,肺牵张感受器兴奋,冲动经迷走神经中的粗纤维传入延髓,在延髓内通过一定的神经联系使吸气切断机制兴奋,切断吸气、转为呼气,即是肺扩张反射。它的生理意义在于能够及时抑制吸气,加速吸气和呼气的交替,使呼吸深度减小,呼吸频率增加,呼吸运动较浅而快。在切断一侧迷走神经后,吸气转为呼气受阻,吸气延长、加深,呼吸运动变得较深而慢。当两侧的迷走神经都被切断后,机体的肺扩张反射便不能进行,呼吸运动就变得更加深而慢了。

解析: 实验设计;
观察、记录家兔呼吸运动;
证明迷走神经对家兔呼吸运动的作用。

阅读理解

Sleep is like food for the brain. Enough sleep helps the body and brain grow and develop. However, many Chinese do not sleep well, and many do not pay enough attention to sleep.

The Chinese Medical Doctor Association released the 2013 China Sleep Quality Index (指数) on March 19 to mark World Sleep Day – March 21.

According to the index, nearly a quarter of Chinese people don’t sleep well. Half said that they feel tired after getting up and 15 percent people have trouble falling asleep.

Ye Jingying, a sleep expert at Beijing Tongren Hospital, says: “If people often wake up during the night, or always feel weak and tired in the day, they should pay attention to their sleep pattern (模式).”

Many people play with their cell phones or iPads before sleeping. The report said that this is one of the main reasons for bad sleep. Other reasons include stress and bad moods.

How to sleep well? Above all, get enough sleep. Seven to nine hours of sleep every night is perfect for an adult, and eight to nine hours is best for a teenager.

Forming good sleep habits is important. The report suggested that people need to keep away from digital devices (数码产品) for at least an hour before sleep. The lights keep their brains excited for a long while. Other suggestions include: try to go to sleep and wake up at the same time every day, even on weekends and during holidays, and do the same relaxing things before bed each night, like listening to soft music.

小题1:From Paragraph 1, which of the following is NOT true?

A.The longer you sleep, the better.

B.Many Chinese people don’t sleep well.

C.Many Chinese people don’t care about sleep.

D.Sleep is very important for our body and brain.小题2:Which of the following means that you sleep well?

A.You feel tired after getting up.

B.You can fall asleep within 20 minutes.

C.You wake up several times during the night.

D.You often do something boring until you feel sleepy.小题3:From the article, which of the following may NOT cause sleeping problems?

A.Reading a book late at night.

B.Having sad or angry feelings.

C.Playing with digital devices before sleeping.

D.Being under strong stress about their life or work.小题4:Which of the following helps teenagers sleep well?

A.They should do different things before sleeping.

B.They should sleep for more than nine hours a day.

C.They should not use any digital devices during the daytime.

D.They’d better go to sleep and get up at the same time every day.

填空题