首页
登录
职称英语
The sensation of pain cannot accurately be described as "located" at the poi
The sensation of pain cannot accurately be described as "located" at the poi
游客
2025-02-25
31
管理
问题
The sensation of pain cannot accurately be described as "located" at the point of an injury, or, for that matter, in any one place in the nerves or brain. Rather, pain signals—and pain relief—are delivered through a highly complex interacting circuitry.
When a cell is injured, a rush of prostaglandin’ s sensitizes nerve endings at the injury. Prostaglandins are chemicals produced in and released from virtually all mammalian cells when they are injured: these are the only pain signals that do not originate in the nervous sys- tern. Aspirin and other similar drugs(such as indomethacin and ibuprofen)keep prostaglandins from being made by interfering with an enzyme known as prostaglandin synthetase, or cyclooxy- genase. The drugs’ effectiveness against pain is proportional to their success in blocking this enzyme at the site of injury.
From nerve endings at the injury, pain signals move to nerves feeding into the spinal cord. The long, tubular membranes of nerve cells carry electrical impulses. When electrical impulses get to the spinal cord, a pain-signaling chemical known as substance P is released there. Substance P then excites nearby neurons to send impulses to the brain. Local anesthetics such as novo-caine and xylocaine work by blocking the electrical transmission along nerves in a particular area. They inhibit the flow of sodium ions through the membranes, making the nerves electrically quiescent; thus no pain signals are sent to the spinal cord or to the brain.
Recent discoveries in the study of pain have involved the brain itself—the supervising organ that notices pain signals and that sends messages down to the spinal cord to regulate incoming pain traffic. Endorphins-—the brain ’ s own morphine—are a class of small peptides that help to block pain signals within the brain itself. The presence of endor- phins may also help to explain differences in response to pain signals, since individuals seem to differ in their ability to produce endorphins. It now appears that a number of techniques for blocking chronic pain—such as acupuncture and electrical stimulation of the central brain stem—involve the release of endorphins in the brain and spinal cord. [br] The passage is primarily concerned with
选项
A、analyzing ways that enzymes and other chemicals influence how the body feels pain.
B、describing the presence of endorphins in the brain and discussing ways the body blocks pain within the brain itself.
C、describing how pain signals are conveyed in the body and discussing ways in which the pain signals can be blocked.
D、demonstrating that pain can be influenced by acupuncture and electrical stimulation of the central brain stem.
E、differentiating the kinds of pain that occur at different points in the body’ s nervous system.
答案
C
解析
主题题型:A.酶和其他化学物质如何影响人体痛感。不全,本文还谈到缓解疼痛问题。B.endorphin,是文中第四段细节。C.正确。描述痛信号在体内如何传播,并讨论抑制痛信号的途径。见原文L5—7,全文都是这个内容的分述。D.针刺和电刺激。原文细节。E.区别人不同位置不同疼痛。无。
转载请注明原文地址:https://tihaiku.com/zcyy/3972079.html
相关试题推荐
Thesensationofpaincannotaccuratelybedescribedas"located"atthepoi
Thesensationofpaincannotaccuratelybedescribedas"located"atthepoi
Arecentcourtdecisionhasqualifieda1998rulingthatworkerscannotbelaid
SurilandcannotbothexportwheatandkeepbreadplentifulandaffordableinSur
Thenewspaperstoryaccuratelyrecountedthehistoryofthecolonialmansion,th
Iftheperimeterofatriangleis18,thenthelengthofoneofthesidesCANNOT
Ifxisaninteger,thentheunitsdigitofxsquaredcannotbeA、0B、1C、2D、5E
TheproductoftwoconsecutivepositiveintegersCANNOTbeA、aprimenumberB、div
WhichofthefollowingCANNOTbeexpressedastheproductofexactly3consecuti
Ifaandbareintegersanda-b=8,then(a+b)CANNOTbeA、0B、lessthan6C、greate
随机试题
[originaltext]Goodevening.I’dliketothanktheContinuingEducationDepartme
[originaltext]M:It’sapityHelencouldn’tcometoseeyouoff,Mary.W:Ikno
丙酮酸羧化酶是哪一个代谢途径的关键酶?( )A.糖异生 B.磷酸戊糖途径
对取得统计从业资格的人员实行统计继续教育。( )
下列各项属于商业银行从事的银行账簿中的外币业务活动的有()。A.外币存款
把下面的图形分为两类,使每一类图形都有各自的共同特征或规律,分类正确的一项是:
请回答血海、足三里的定位、归经及操作。(10分)
A.白豆蔻B.苍术C.广藿香D.厚朴E.砂仁治疗夜盲症,宜选用
经皮吸收制剂的类型中不包括()()A.凝胶膏剂 B.充填封闭型 C.骨架扩散
建筑安装工程费按照造价形成可划分成()。A、分部分项工程费 B、措施项目费
最新回复
(
0
)