Sleet is part of a person’s daily activity cycle. There are several different stages of sleep, and they too occur in cycles. If you are an average sleeper, your sleep cycle is as follows. When you fist drift off into slumber, your eyes will roll about a bit, you temperature will drop slightly, your muscles will relax, and your breathing well slow and become quite regular. Your brain waves slow and become quite regular. Your brain waves slow down a bit too, with the alpha rhythm of rather fast waves 1 sleep. For the next half hour or so, as you relax more and more, you will drift down through stage 2 and stage 3 sleep. The lower your stage of sleep. slower your brain waves will be. Then about 40to 69 minutes after you lose consciousness you will have reached the deepest sleep of all. Your brain will show the large slow waves that are known as the delta rhythm. This is stage 4 sleep.

You do not remain at this deep fourth stage all night long, but instead about 80 minutes after you fall into slumber, your brain activity level will increase again slightly. The delta rhythm will disappear, to be replaced by the activity pattern of brain waves. Your eyes will begin to dart around under your closed eyelids as if you were looking at something occurring in front of you. This period of rapid eye movement lasts for some 8 to 15 minutes and is called REM sleep. It is during REM sleep period, your body will soon relax again, your breathing will slip gently back from stage 1 to stage 4 sleep----only to rise once again to the surface of near consciousness some 80 minutes later.

【真题】辽宁省阜新市2018年中考英语试题及答案(Word版) 18-08-01

【真题】山东省菏泽市2018年中考英语试题及答案(Word版) 18-08-01

【真题】四川省绵阳市2018年中考英语试题及答案(Word版) 18-07-31

【真题】浙江省台州市2018年中考英语试题及答案(Word版) 18-07-31

【真题】湖北省荆州市2018年中考英语试题及答案(Word版) 18-07-31

大庆市肇源县2018年外研版七年级上期末英语试卷含解析 18-07-29

【真题】2018年衡阳市中考英语试卷及答案解析(Word版) 18-07-24

【真题】2018年无锡市中考英语试卷及答案解析(Word版) 18-07-24

2018年云南省中考英语试题（原卷+解析） 18-07-24

2018年春外研版七年级英语下期末测试卷（二）含听力mp3 18-07-23

外研版九年级上英语Module1检测题及答案（含听力原文） 18-07-23

＊ 本站是所有资料仅供教学之用。本站部分内容来自互联网或由会员上传，版权归原作者所有，如有问题，请及时联系我们。

版权所有@12999教育资源网