问题 实验题

(8分)图为屈肘和伸肘示意图,请回答问题:

(1)图中的①是       ,当人屈肘时,以它为主的肌肉处于         状态,而以②        为主的肌肉处于       状态。

(2) 当人伸肘时,①处于         状态,②处于             状态。

(3)当双臂垂直提起重物时,①和②均处于                  状态。

(4)不管是屈肘还是伸肘都要           传来的刺激,肌肉才能完成收缩。

答案

(1) 肱二头肌,收缩;肱三头肌,舒张。

(2)舒张,收缩。 (3)收缩;  (4) 神经。

题目分析:由肌肉的协作关系示意图可知:①是]肱二头肌,②是肱三头肌,图A表示屈肘动作的产生,图B表示伸肘动作的产生,骨骼肌有受刺激而收缩的特性,当骨骼肌受神经传来的刺激收缩时,就会牵动骨绕着关节活动,于是躯体就会产生运动,但骨骼肌只能收缩牵拉骨而不能推开骨,因此与骨相连的肌肉总是由两组肌肉相互配合活动的,例如,屈肘动作和伸肘动作的产生,屈肘时,肱二头肌收缩,肱三头肌舒张,伸肘时,肱三头肌收缩,肱二头肌舒张,双臂垂直提起重物时,肱二头肌和肱三头肌都收缩。

点评:解题时,特别是有关高等动物的运动和生理方面的问题,都可以拿自己做“模特”进行现场“实验”,然后从中获取信息达到解题的目的。

阅读理解

阅读理解。

     No one is glad to hear that his body has to be cut open by a surgeon (外科医生) and part of it taken out.

Today, however, we needn't worry about feeling pain during the operation. The sick person falls into a kind

of sleep, and when he awakes, the operation is finished. But these happy conditions are fairly new. It is not

many years since a man who had to have operation felt all its pain.

     Long ago, operation had usually to be done while the sick man could feel everything. The sick man had to

be held down on a table by force while the doctors did their best for him. He could feel all the pain if his leg or

arm was being cut off, and his fearful cries filled the room and the hearts of those who watched.

     Soon after 1770, Josept Priestley discovered a gas which is now called "laughing gas". Laughing gas

became known in America. Young men and women went to parties to try it. Most of them spent their time

laughing, but one man at a party, Horace Wells, noticed that people didn't seem to feel pain when they were

using this gas. He decided to make an experiment on himself. He asked a friend to help him.

     Wells took some of the gas, and his friend pulled out one of Well's teeth. Wells felt no pain at all. As he

didn't know enough about laughing gas, he gave a man less gas than he should have. The man cried out with

pain when his tooth was being pulled out.

     Wells tried again, but this time he gave too much of the gas, and the man died. Wells never forgot this

terrible event.

1. It is _______since a man being operated felt all the pain.

A. a few more years

B. not long

C. few years

D. two thousand years

2. Long ago, when the sick man was operated on, he ________.

A. could feel nothing

B. could not want anything

C. could feel all the pain

D. could do anything

3. Using the laughing gas, the people did not seem to ________.

A. be afraid of anything

B. feel pain

C. want to go to the parties

D. be ill

4. If a man took less laughing gas than he should have when an operation went on he _______.

A. felt nothing

B. felt very comfortable

C. still felt pain

D. would die

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