新东方在线网络课堂 雅思 新东方在线 > 雅思 > 雅思真题 > 雅思模拟题 > 正文

雅思阅读模拟题:Hormones in the Body

2017-05-28 10:42:00 来源:新东方在线雅思资料下载

微博用户专属

雅思

@新东方雅思考试

+关注免费送

¥1999
新东方内部资料

  新东方在线雅思网特为大家准备了雅思阅读模拟题:Hormones in the Body。雅思模拟试题在雅思备考过程中所起的作用不可小觑,通过模拟练习题,我们可以很直接地了解到自己的备考状况,从而可以更有针对性地进行之后的复习。希望以下内容能够对大家的雅思备考有所帮助!更多雅思报名官网的最新消息,最新、最专业的雅思备考资料,新东方在线雅思网将第一时间为大家发布。

  Hormones in the Body

  Up to the beginning of the twentieth century, the nervous system was thought to control all communication within the body and the resulting integration of behavior. Scientists had determined that nerves ran, essentially, on electrical impulses. These impulses were thought to be the engine for thought, emotion, movement, and internal processes such as digestion. However, experiments by William Bayliss and Ernest Starling on the chemical secretin, which is produced in the small intestine when food enters the stomach, eventually challenged that view. From the small intestine, secretin travels through the bloodstream to the pancreas. There, it stimulates the release of digestive chemicals. In this fashion, the intestinal cells that produce secretin ultimately regulate the production of different chemicals in a different organ, the pancreas.

  Such a coordination of processes had been thought to require control by the nervous system; Bayliss and Starling showed that it could occur through chemicals alone. This discovery spurred Starling to coin the term hormone to refer to secretin, taking it from the Greek word hormon, meaning “to excite” or “to set in motion.” A hormone is a chemical produced by one tissue to make things happen elsewhere.

  As more hormones were discovered, they were categorized, primarily according to the process by which they operated on the body. Some glands (which make up the endocrine system) secrete hormones directly into the bloodstream. Such glands include the thyroid and the pituitary. The exocrine system consists of organs and glands that produce substances that are used outside the bloodstream, primarily for digestion. The pancreas is one such organ, although it secretes some chemicals into the blood and thus is also part of the endocrine system.

  Much has been learned about hormones since their discovery. Some play such key roles in regulating bodily processes or behavior that their absence would cause immediate death. The most abundant hormones have effects that are less obviously urgent but can be more far-reaching and difficult to track: They modify moods and affect human behavior, even some behavior we normally think of as voluntary. Hormonal systems are very intricate. Even minute amounts of the right chemicals can suppress appetite, calm aggression, and change the attitude of a parent toward a child. Certain hormones accelerate the development of the body, regulating growth and form; others may even define an individual’s personality characteristics. The quantities and proportions of hormones produced change with age, so scientists have given a great deal of study to shifts in the endocrine system over time in the hopes of alleviating ailments associated with aging.

  In fact, some hormone therapies are already very common. A combination of estrogen and progesterone has been prescribed for decades to women who want to reduce mood swings, sudden changes in body temperature, and other discomforts caused by lower natural levels of those hormones as they enter middle age. Known as hormone replacement therapy (HRT), the treatment was also believed to prevent weakening of the bones. At least one study has linked HRT with a heightened risk of heart disease and certain types of cancer. HRT may also increase the likelihood that blood clots—dangerous because they could travel through the bloodstream and block major blood vessels—will form. Some proponents of HRT have tempered their enthusiasm in the face of this new evidence, recommending it only to patients whose symptoms interfere with their abilities to live normal lives.

  Human growth hormone may also be given to patients who are secreting abnormally low amounts on their own. Because of the complicated effects growth hormone has on the body, such treatments are generally restricted to children who would be pathologically small in stature without it. Growth hormone affects not just physical size but also the digestion of food and the aging process. Researchers and family physicians tend to agree that it is foolhardy to dispense it in cases in which the risks are not clearly outweighed by the benefits.


本文关键字: 雅思阅读 雅思模拟题

为你特别匹配的雅思超值课程,快速提分先人一步!
  • 【知心雅思】雅思全能6.5分班(免费体验版)

    适合人群:雅思成绩目标6.5分的考生

    课时:227

    查看详情
  • 【知心雅思】雅思全能7分班(免费体验版)

    适合人群:雅思成绩目标7分的考生

    课时:227

    查看详情
  • 雅思新生预科班

    适合人群:需要提高雅思备考基本功的考生

    课时:55

    查看详情
  • 雅思核心1200词背诵

    适合人群:有背单词困难症的考生

    课时:44

    查看详情
  • 剑桥雅思真题集精讲解析(90天畅学)

    适合人群:任何阶段的雅思考生

    课时:120

    查看详情

课程试听换一换

  • 5天密训:雅思口语拯救计划

    ¥199

  • 【知心雅思】雅思全能7分旗舰外教VIP全程班

    ¥4880

  • 【暑期过雅思】屠鸭预备营

    ¥1

  • 【知心雅思】雅思全能7分VIP全程班

    ¥2480

  • 【知心雅思】雅思全能6.5分旗舰外教VIP全程班

    ¥4380

  • 【知心雅思】雅思全能6.5分VIP全程班

    ¥2180

  • 【知心雅思】雅思全能7分旗舰外教VIP长...

    ¥6880

  • 【知心雅思】 雅思全能7分直达班

    ¥1480

分享到:

相关推荐

版权及免责声明

1,"新东方在线"上的内容,包括文章、资料、资讯等, 本网注明"稿件来源:新东方在线"的,其版权 均为"新东方在线"或北京新东方迅程网络科技有限公司所有 ,任何公司、媒体、网站或个人未经授权不得转载、链接、转贴或以其他方式使用。已经得到 "新东方在线"许可 的媒体、网站,在使用时必须注明"稿件来源:新东方",违者本网站将依法追究责任。

2, "新东方在线" 未注明"稿件来源:新东方"的 文章、资料、资讯等 均为转载稿,本网站转载出于传递更多信息之目的,并不意味着赞同其观点或证实其内容的真实性。如其他媒体、网站或个人从本网站下载使用,必须保留本网站注明的"稿件来源",并自负版权等法律责任。如擅自篡改为 " 稿件来源:新东方 " ,本网站将依法追究其法律责任。

3,如本网转载稿涉及版权等问题,请作者见稿后在两周内与新东方在线联系。

  • 雅思冲7分外教旗舰vip班
  • 英语词汇量测试
  • 2017雅思真题回忆及答案解析
  • 雅思口语全程备考攻略
  • 快速攻克雅思移民

热点资讯更多>>

实用 • 工具

雅思课程排行榜本周本月

交流 • 下载

雅思公开课更多>>

小明NENG雅思第一弹-有一个地方 w 17分30秒
1 小明NENG雅思第一弹-有一个地方
小明NENG雅思第五弹-宿醉2欢乐来袭 w 12分26秒
2 小明NENG雅思第五弹-宿醉2欢乐来袭
小明NENG雅思第四弹-宿醉1中的有趣表达 w 10分46秒
3 小明NENG雅思第四弹-宿醉1中的有趣表达
小明NENG雅思第十弹-跟小明听歌学口语 w 10分27秒
4 小明NENG雅思第十弹-跟小明听歌学口语
小明NENG雅思第三弹-搞怪电影里的地道表达 w 12分38秒
5 小明NENG雅思第三弹-搞怪电影里的地道表达

推荐阅读