问题 实验题

据调查,我国的近视眼发病率高居世界第二位,近视逐渐低龄化,发病率呈逐年上升趋势,这引起了人们对学生用眼卫生的高度关注。下图是眼球结构、近视眼成像及矫正原理示意图,请分析回答:

(1)分析上图眼球的结构,在不同光亮程度的环境中,眼球会通过调节[ ]_________的大小,从而调节进入眼球的光量。物体发出的光线,进入眼球时首先穿过的结构是[ ]_________。通过[ ]________的调节作用,物象最终落在[ ]_______上,人才能清晰地看到这个物体。

(2)近视眼是由于眼球过度疲劳,造成某些结构变化不能复原。下图中,能正确表示近视眼戴眼镜前后成像原理的分别是(   )、(   )。

(3)若人的眼球结构完好无损,但是看不见周围的物体,则发生病变的部位可能是________________________。

(4)汽车司机看见路口红灯立即停车。这一反射过程中能将红灯的刺激转变为神经冲动的是眼球中的[ ]_________。从反射形成的过程看,此反射属于________。

(5)注意眼的清洁卫生,不用脏手擦眼睛,不和他人共用毛巾等,可以避免结膜炎、沙眼等传染病的传染,这在传染病预防措施上属于_______________________。

答案

(1)2瞳孔   1角膜   3晶状体   7视网膜  (2)甲 丙

(3)视神经或视觉中枢     (4)视网膜  条件反射  (5)切断传播途径

题目分析:(1)图示中1角膜,2瞳孔,3晶状体,4虹膜,5巩膜,6脉络膜,7视网膜, ①我们之所以能看远近不同的物体,原因是眼球成像过程中,起主要调节作用的结构是3晶状体,视觉的形成过程是:外界物体反射来的光线,经过角膜、房水,由瞳孔进入眼球内部,再经过晶状体和玻璃体的折射作用,在视网膜上能形成清晰的物像,物像刺激了视网膜上的感光细胞,这些感光细胞产生的神经冲动,沿着视神经传到大脑皮层的视觉中枢,就形成视觉。

(2)长时间的近距离作业,如读书、写字、看电视、玩游戏机等,或光线过暗,使眼睛长时间的调节紧张,头部前倾,眼球内不断的充血,眼内压相应的增高,以及眼外肌的紧张和压迫眼球,使睫状体持续收缩,调节负担过重,导致晶状体过度变凸,不能恢复成原状,或者因调节时牵引涡状静脉,妨碍了血液的流通,使巩膜的抵抗力减弱,严重时使眼球的前后径过长,使远处物体反射来的光线形成的物像,落在视网膜的前方,因此不能看清远处的物体,形成近视,需要配戴凹透镜矫正,图甲是近视眼,佩戴凹透镜后市图丙。

(3)眼球结构完好无损,但是看不见周围的物体,可能是视神经或视觉中枢发生病变。

(4)司机看到红灯刹车是出生后才有的,是在非条件反射的基础上,经过一定的过程,在大脑皮层参与下完成的复杂反射。

(5)注意眼的清洁卫生,不用脏手擦眼睛,不和他人共用毛巾等,可以避免结膜炎、沙眼等传染病的传染,这在传染病预防措施上属于切断传播途径。

单项选择题
阅读理解

阅读理解。

    There were many beautiful buildings in ancient Rome, but the living conditions for ordinary people

were bad. Most of their homes were so poorly made that they fell down or were fire hazards  (=danger)  with their steep, narrow wooden stairways. Most people were packed into apartment buildings that

rose shakily (=unsafely) six to twelve floors above the ground. The apartments were rooms about three

metres square, and each building housed about five hundred people.

    These tall buildings faced each other across streets only three metres wide, so no sunlight reached the    ground. Even so, apartments were costly, though cheaper places could be had outside Rome. But people wanted to be near their work and entertainment. So the streets became crowded and it was hard to move quickly. At night, the streets were filled with noise as food and supplies were brought  inthe city on wagons and carts.

1. In ancient Rome, most people lived in ________ apartments.

A. small and crowded

B. clean and tidy

C. spacious and sunny

D. tall and big

2. The streets in ancient Rome were ________.

A. crowded and noisy

B. wide and bright

C. narrow and dark

D. both A and C

3. People liked to live in Rome Because________.

A. the apartments were comfortable

B. the living expenses were low

C. they have no money to build houses outside the city

D. they wanted to enjoy the conveniences of the city

4. This passage is mainly about ________ in ancient Rome.

A. the beautiful buildings

B. the living conditions of ordinary people

C. the streets and transportation

D. the food and daily supplies