【英语时差8,16】咖啡因的作用
时间：2019-01-22 作者：英语课 分类：英语时差8，16
Coffee And Caffeine: How Caffeine Makes You Feel More Awake Some people aren't able to function without that first cup of coffee in the morning. We'll look at how caffeine in coffee makes you feel more awake and alert. Soon after you drink a cup of coffee, caffeine, a strong stimulant 1 is absorbed into your intestinal 2 tract 3 and into your blood. Peak absorption occurs in less than an hour, usually within thirty minutes. Once absorbed, it is rapidly distributed into all of your body’s fluids, then processed by your liver and eventually excreted in urine. Three hours after you drink a cup of coffee, the level of caffeine in your blood will be half of what it was at its peak. Six hours after drinking coffee, you will have eliminated most of the caffeine from your system. Once caffeine is distributed throughout the body, it stimulates 4 your nerves and causes adrenalin to be released. Adrenalin is the main neuro-transmitter that changes your levels of energy and alertness. Adrenalin increases your heart rate, which results in more blood pumped per minute. This blood carries extra oxygen to your brain, making you feel more alert. Caffeine also directly stimulates the spinal 5 cord and the cortex of the brain, which enhances these alert feelings. Many people experience a dip in energy several hours after drinking coffee. Though scientists aren’t exactly certain why this happens, a possible explanation may be that, after the effects of caffeine wear off, your brain needs to adjust to working without the stimulus 6 the caffeine provided. So, though that first cup of coffee might get you going in the morning, it might also leave you feeling fatigued 7 half way through the day.
- It is used in medicine for its stimulant quality.由于它有兴奋剂的特性而被应用于医学。
- Musk is used for perfume and stimulant.麝香可以用作香料和兴奋剂。
- A few other conditions are in high intestinal obstruction. 其它少数情况是高位肠梗阻。 来自辞典例句
- This complication has occasionally occurred following the use of intestinal antiseptics. 这种并发症偶而发生在使用肠道抗菌剂上。 来自辞典例句
- He owns a large tract of forest.他拥有一大片森林。
- He wrote a tract on this subject.他曾对此写了一篇短文。
- Exercise stimulates the body. 运动促进身体健康。 来自《简明英汉词典》
- Alcohol stimulates the action of the heart. 酒刺激心脏的活动。 来自《现代英汉综合大词典》
- After three days in Japan,the spinal column becomes extraordinarily flexible.在日本三天，就已经使脊椎骨变得富有弹性了。
- Your spinal column is made up of 24 movable vertebrae.你的脊柱由24个活动的脊椎骨构成。
- Regard each failure as a stimulus to further efforts.把每次失利看成对进一步努力的激励。
- Light is a stimulus to growth in plants.光是促进植物生长的一个因素。