问题 单项选择题

我国科学家成功破解了神经元“沉默突触”的沉默之谜,这类突触只有突触结构没有信息传递功能。如图所示的反射弧中具有“沉默突触”。其中—○—<表示从树突到胞体,再到轴突及末梢。下列有关说法正确的是()

A.若③为该反射弧的神经中枢,神经中枢内一定具有“沉默突触”

B.如果神经元内不能合成神经递质或者突触后膜缺乏相应受体,可能形成“沉默突触”

C.该反射弧的信息传导途径一定是①→②→③→④→⑤

D.若图中③为“沉默突触”,则刺激①不能引起e处的电位变化,同时⑤检测不到反应

答案

参考答案:B

解析:③处可能有沉默突触,也可能没有,A错误;沉默突触没有信息传递功能,可能是没有神经递质,也可能是没有受体不能识别递质,B正确;反射弧的信息传导途径也可能是①→②→④→⑤,C错误;若③是沉默突触,信息可从②→④,所以刺激①,能引起e处电位变化,D错误。考点:本题考查反射弧相关知识,意在考查考生能从课外材料中获取相关的生物学信息,并能运用这些信息,结合所学知识解决相关的生物学问题。

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"He looks normal." That's what everybody says when I tell them my son was just diagnosed as autism (孤
独症). They all say it without   1  .
    It's true. Alejandro does look like every other   2  boy. He plays, he smiles, and he runs around with the
two-year-old boy's boundless  3  until he is too tired. He laughs when you move your fingers  4  on a
sensitive part of his body. And he often   5    his toys like every other young child at his age.
    But most of the time, Alejandro   6    in his own little world playing with his toys all by himself   7    in a
group of kids and   8    you when you talk to him loudly. At that time he's alone, no matter how hard you
try to    9  him.
    My wife and I get   10  . We ask for "nose kisses" or hugs and many times he doesn't  11 us. It's
extremely anxious when your child's face is right in front of you and he won't admit your   12   .
   He regularly doesn't eat. The food often   13    him when he puts it in his mouth. He is very small   14   
his age. We are told that it's another  15   of the autism.
   Because autism isn't like some other   16  , there is no set treatment. Each child needs to be treated 
  17  ; what works for one probably doesn't work for another. Try a treatment. If it doesn't work, you have
to try another   18   you hopefully find something that does work.
    The future is cloudy, but we will try everything we can do to reach him, because we love him and we
know he's a(n)   19    little boy. And we believe with the help of love, we can    20 any difficulty.
( )1. A. exception      
( )2. A. naughty        
( )3. A. force          
( )4. A. lightly        
( )5. A. gets along with
( )6. A. exists        
( )7. A. seldom        
( )8. A. watching      
( )9. A. reach          
( )10. A. tired        
( )11. A. recognize    
( )12. A. appearance    
( )13. A. pleases      
( )14. A. at            
( )15. A. usage        
( )16. A. diseases      
( )17. A. equally      
( )18. A. unless        
( )19. A. clever        
( )20. A. treat        
B. problem      
B. normal        
B. power        
B. secretly      
B. deals with    
B. sleeps        
B. even          
B. teasing      
B. wake          
B. bored        
B. understand    
B. impression    
B. bothers      
B. for          
B. advantage    
B. causes        
B. individually  
B. when          
B. special      
B. experience    
C. discussion  
C. alone        
C. energy      
C. heavily      
C. puts up with
C. studies      
C. only        
C. ignoring    
C. relieve      
C. discouraged  
C. notice      
C. presence    
C. relaxes      
C. under        
C. function    
C. factors      
C. similarly    
C. until        
C. foolish      
C. discover    
D. question      
D. stupid        
D. imagination    
D. greatly        
D. plays with    
D. works          
D. never          
D. listening      
D. comfort        
D. upset          
D. remember      
D. satisfaction  
D. delights      
D. over          
D. effect        
D. sufferings    
D. usually        
D. though        
D. pleasant      
D. overcome      
问答题 简答题