有关医学的英语文章
Unit1肺和肾的功能
肺的血管系统
肺从两个血管系统----支气管循环系统和肺循环系统获得血液供应。它的营养血液于支气管循环系统,流向肺部除肺泡外的所有组织,因为支气管循环系统始于主动脉及上肋间动脉,接受大约1%的心输出量。大约三分之一的支气管循环的静脉输出流入全身静脉,然后回到右心房。剩余的输出流入肺静脉,并在心脏最小静脉的作用下,在正常情况下,以1%-2%的量自右向左分流。
肺动脉系统沿着气道从肺门向外周延伸,向下连接下段气道(直径大约2毫米)的动脉,它们壁薄且富有弹性。从这儿开始,动脉成肌肉化发展,直至其达到30微米,此时肌层消失。因为这些小肌肉动脉起着积极控制肺部血流分布的作用,所以大部分动脉压降产生在这些小肌肉动脉中。肺小动脉将血液排空,送入广泛分布的毛细血管网,进入肺静脉。肺静脉的壁很薄,它们最终在肺门处与动脉和支气管汇合,出肺进入左心房。
肾结构成分
人类肾脏在解剖学上位于腹膜后隙,与下胸椎和上腰椎平行。每个成年人的肾脏大约重150克,长、宽、厚分别为12厘米、6厘米以及3厘米。肾脏的冠状部分分为/由两个明确的区域(组成)。外周部的皮质大约1厘米厚,深部的髓质由几个肾锥体构成。这些锥体状结构的底部位于皮髓质结合处。锥体的顶部伸入肾门,称为肾**。每个肾**被一个肾小盏包裹。肾小盏与肾大盏相聚组成肾盂。经肾**流出的尿液汇集在肾盂,通过输尿管
排入膀胱。 由主动脉分支出来的肾总动脉为两肾输送血液。肾总动脉通常分为两个主侧支,这两个侧支又进一步分为叶动脉,为肾脏上、中、下区域供应血液。当这些血管进入肾实质,变成叶间动脉通向肾皮质时,(这些血管)又进一步细分。细分后的更小血管在皮髓质结合处成为竖支--弓状动脉。从弓状动脉伸出的叶间动脉进入皮质。由于传入小动脉始于这些末端叶间动脉,所以为肾小球毛细血管输送血液。
组织学上,肾脏是由一个叫做“肾单位”的基本单位组成。每个肾脏约含有一百万个肾单位,“肾单位”有两个主要成分:过滤成分―紧包着毛细血管网(肾小球)和一个附着在上面的小管组成。这个小管包含几个明显的解剖和功能成分。
Unit 2细胞与衰老
衰老是一种正常的生理过程,伴有肌体内平衡适应性反应的进行性改变。研究老年人健康问题和保健的特殊分支称作老年医学。
衰老的明显特征众所周知:头发花白和脱落,牙齿脱落,皮肤起皱,肌肉减少,脂肪积存增加。衰老的生理征兆是肌体对环境压力反应的功能和能力逐渐减退.。如同保持不断地体内平衡应对温度、饮食和氧供反应变慢一样,机体代谢也减慢了。衰老的这些迹象与机体中细胞数的净减少及存余细胞的功能缺失有关。
衰老的另一个表现是组织的细胞外成分也随年龄的变化而变化。负责肌腱力量的胶原纤维的数量增加,而质量却随着衰老降低。动脉壁胶原质中的变化造成动脉壁伸展性缺失,如同动脉壁上的积聚物造成动脉粥样硬化(即动脉壁脂肪物质堆积)一样。弹性蛋白是另一种细胞外成分,主要负责血管和皮肤的弹性。随着年龄的变化,它的变粗,变碎并需要获得更大的钙亲和力,这些可能也是造成动脉粥样硬化的原因。
葡萄糖在机体中是最丰富的糖类,它在衰老的过程中也可能起作用。根据一个假设,任意给细胞内外的蛋白质增加葡萄糖,结果会在相邻蛋白质分子间形成不可逆交联。当人衰老时,会形成更多的交联,这可能导致正在衰老的组织变得僵化,丧失弹性。
虽然正常情况下,每分钟会有好几百万的新细胞产生,但人体有几种细胞:心脏细胞,骨骼
肌纤维细胞,神经细胞是无法替代的。实验显示,许多种类的细胞分裂能力有限。在机体外生长的细胞仅仅分裂几次就停止了。细胞分裂数与捐献者的年龄有关,与这些细胞获取的不同物种的正常寿命有关。这些发现为这种假说提供了有力证据,即细胞有丝分裂的终止是正常的,有基因决定的。根据这个观点,衰老基因是出生时就存在的基因蓝图的一部分,它取决于生命攸关的减慢或停止过程出现的特定时间。
衰老的另一个理论即自由基理论。自由基是含有未配对电子的带电荷分子。这是一种不稳定的高反应性分子,容易损害蛋白质。自由基的影响有:皮肤起皱,关节僵直,动脉硬化。自由基也可以损害DNA。造成自由基的因素有:空气污染,放射线以及我们摄取的某些食物。 饮食中的其他物质如维生素E,维生素C,β-胡萝卜素以及硒都是抗氧化剂,可以抑制自由基形成。最近的两个研究支持了衰老的自由基理论。孕育健康长寿的果蝇株产生超正常量的酶:过氧歧化酶。它可以中和自由基。同样,把产生过氧歧化酶的基因注射进果蝇胚胎会延长其平均寿命。
然而,关于衰老的理论,有些是在细胞水平上解释其过程,有的则强调整个生物体内运作的调节机制,比如免疫系统产生各种抗异物侵扰的抗体,可是会对细胞本身发起攻击。这种自身免疫应答可能是细胞表面变化造成,引起抗体附加并标记出破坏细胞。当细胞表面变化增加,自身免疫应答加强,产生众所周知的衰老。
Unit 3生物化学和人类发展
生物化学是在细胞和分子水平上运用化学研究生物过程的学科。(省略2句)生物化学使用化学、物理学、分子生物学和免疫学研究在生物物质中发现的复杂分子的结构与行为,研究那些分子相互作用构成细胞、组织和整个生物体的方式。生物学涉及从基因移植到巨分子结构和功能的广阔的细胞功能范围。
?比如:单分子DNA如何复制生成其本身两个完全相同的副本,DNA分子中基础序列如何确定编码蛋白质中氨基酸的序列。我们以详细的机械术语描述这些(生物)进程的能力为其他生物科学研究奠定了坚实的化学基础。再者,我们把基础生命过程理解为化学结构和反应,比如遗传信息的传输,这种意识具有重要的哲学含义。??
第二,??导致镰状细胞贫血、囊性纤维化、血友病和许多其他遗传疾病的分子病变在生物化学的水平上得以阐述。一些导致癌症发生的分子事物得以识别。了解基本的缺陷为发现有效的治疗方法开启了大门。生物化学使得合理设计新药成为可能,包括病毒(如HIV病毒)复制所需的酶的特殊抑制剂。生物工程制造的细菌或其他生物可以用来作为制造有价值蛋白质的工厂,如胰岛素和血细胞发育的诱导剂。
生物化学非常有助于临床诊断。??DNA probes DNA探针在遗传疾病,传染性疾病以及癌症的精确诊断中越来越起作用。农业也应生物化学的发展受益匪浅,产生了更加有效的、对环境无害的除草剂、杀虫剂。基因工程植物更能抵抗虫害。所有这些努力因基因组测序的进展而加速发展。
第三,生物化学的进展正在使研究者们研究一些生物和医学上最令人激动得问题。受精卵如何会产生与肌肉、大脑和肝脏细胞不同的细胞?感官是如何工作的?大脑疾病如老
年痴呆症和精神分裂症的分子基础是什么?免疫系统如何区分自我和非自我?长期记忆和短期记忆的分子机制是什么?对于这些问题的答案,过去曾经似乎很遥远,现在已经得到初步解答,并且可能在不久的将来得到更加全面的解答。
unit 4 病理学简介_有关医学的英语文章。
病理学是研究疾病的科学。在临床实践和医学教学中,病理学的含义更为广泛:病理学由一系列的知识、观点和研究方法构成,它们对理解现代医学及医学实践至关重要。
病理学不等同于疾病组织的形态学,把两者等同起来是一种过时的看法。病理学包括对疾病功能及结构的认识和理解,包含从分子水平到对个体的影响。
随着新科学方法的应用,人们更深入地了解疾病,病理学所涵盖的内容也会不断地改变、更新和拓展。
病理学的最终目的在于确定疾病的原因,从而达到防治疾病的基本目标。
病理学的范围
病理学是医学科学和实践的基础。没有病理学,医学实践也将无从谈起。
临床病理学和实验病理学
人们对疾病的认识于对病人的观察,同样也于对动物和细胞培养的实验性研究。而最大的贡献则于对病体组织和体液的深入研究。
临床病理学
临床医学以对疾病的纵向研究为基础,即研究病人病史,检查、研究和治疗疾病。而临床病理学更关注疾病本身的现况分析,深层次研究发病原因和机制,以及疾病对人体各个器官和系统的影响。两者相辅相成、不可分割。不理解病理学,临床医学无从开展;而没有了临床意义,病理学也就失去了存在价值。
实验病理学
实验病理学观察诸如疾病动物模型或细胞培养等实验系统的操作效果。幸运的是,细胞培养技术在进步,所以在医学研究和实验病理学中,人们对实验动物的使用减少了。然而,通过细胞培养复制完整人体中普遍存在的生理环境仍然是一种极其困难的尝试。
病理学的分支
病理学是一门拥有庞大分支的学科。在实践中,病理学包含以下几大分支:
组织病理学:通过对组织的检查研究和诊断疾病。
细胞病理学:通过对单个细胞的检查研究和诊断疾病。
血液病学:对血液中细胞成分和可凝结成分的异常进行研究。
微生物学:对传染性疾病及相关生物体进行研究。
免疫学:对机体特殊防御机制进行研究。
病理化学:从组织和体液的变化中研究和诊断疾病。
遗传学:对异常染色体和基因进行研究。
毒理学:对已知或疑似毒物的作用进行研究。
法医病理学:病理学在法律中的应用,比如对可疑情况下的死亡进行调查。
由于这些分支都拥有各自的专业人士队伍,对病理学进行划分的专业意义大于它的教育意义。病理学的教学必须着眼于整体,因为在这些常规分类中机体和疾病是没有区分的。 因此,该书采用多学科方法阐述病理学。系统病理学部分概述各器官的正常结构与功能,描述各临床症状和体征的病理学基础,强调了各疾病的临床意义。
普通病理学和系统病理学
病理学教学内容分为两部分:
普通病理学:研究和阐明主要疾病过程的机制和特点,如先天性疾病和后天性疾病、炎症、肿瘤和恶化等。
系统病理学:描述影响各器官或器官系统的各种疾病,如阑尾炎、肺癌和动脉粥样化等。 普通病理学
普通病理学(总论)研究和阐明存在于各主要疾病的共同病因、发病机制和特点。 本书第二部分包含这些内容,举例说明各种疾病。在学习系统病理学之前,理解普通病理学的各原
理至关重要。普通病理学是学习各种疾病系统病理学之前所必须具备的理论基础。 系统病理学
系统病理学(各论)研究和阐明影响各器官或器官系统的各种疾病。(注意区分“系统的”和“人体的”在本文中的使用。人体病理学具有遍及所有人体系统的疾病的特性!)每种疾病通常是由于普通病理学中最具特征的一类或更多种类的原因和发病机制造成。因此,急性阑尾炎是影响阑尾的急性炎症;肺癌是肺细胞受到致癌作用的结果;而因此形成的癌细胞的行为会遵循已确立的恶性肿瘤的模式,等等。
unit5
Innate immunity (also called natural or native immunity ) provides the early line of defense against microbes. it consists of cellular and biochemical defense mechanisms that are in place even before infection and are poised to respond rapidly to infections .These mechanisms react to microbes and to the products of injured cells . and they respond in essentially the same way to repeated
infections .The principal ponents of innate immunity are (1) physical and chemical barriers. such as epithelia and antimicrobial chemicals Produced at epithelial surfaces: (2) phagocytic cells (neutrophils, macrophages) , dendritic cells. and natural killer (NK) cells: (3) blood proteins, including members of the plement system and other mediators of inflammation; and (4) proteins called cytokines that regulate and coordinate many of the activities of the cells of innate immunity. The mechanisms of innate immunity are specific for structures that are mon to groups of related microbes and may not ,distinguish fine differences between microbes. 固有免疫(又叫自然免疫或者先天性免疫)为抵制微生物提供了早期的天然防线。它有细
胞和生化机制构成,他们甚至在感染之前就已经开始运转,随时准备迅速应对感染。这些机制对微生物和受损细胞的产生做出反应,也已基本相同的方式应对重复感染。固有免疫主要成分是1.物理和化学屏障,比如上皮组织和上皮表层产生的抗菌化学物。2.噬菌细胞(嗜中性粒细胞,巨噬细胞),树突状细胞和自然杀伤细胞。3.血蛋白,包括补体系统的成分和其他的炎症介质。4.一种叫做细胞因子的蛋白质能够调节和协调固有免疫的细胞活动。固有免疫机制是专门针对成组的相关联微生物共同拥有的结构的,他们可能无法分辨为生物之间的细小差别。 In contrast to innate immunity. there are other immune responses that stimulated by exposure to infectious agents and increase in magnitude and defensive capabilities with each suessive exposure to a particular microbe Because this form of immunity develops as a response to infection and adapts to the infection. it is called adaptive immunity. The defining characteristics of adaptive immunity are exquisite specificity for distinct molecules and an ability to \"remember\" and respond more vigorously to repeated exposures to the same microbe .The adaptive immune system is able lo recognize and react to a large number of microbial and nonmicrobial substances. In addition. it has an extraordinary capacity to distinguish between different , even closely related, microbes and molecules, and for this reason it IS also called specific immunity. It is also sometimes called acquired immunity. to emphasize that potent protective responses are “acquired\" by experience .The main ponents of adaptive immunity are cells called lymphocytes and their secreted products. such as antibodies. Foreign substances that induce specific immune responses or are recognized by Symphocytes or antibodies are called antigens. 与固有免疫相比,因接触感染因子而被激活的其它的免疫反应会因为与某一种微生物的反复接触而体积增大和防御能力增强。因为这种形式的免疫会随着对感染的反应而发展和调整,因此叫做适应性反应。适应性免疫的明确特征是对不同的分子有敏锐的特异性,他有记忆的功能能够对相同微生物的重复
感染做出更加激烈的应答。适应
性免疫系统能够识别,并对大量的微生物和非微生物产生应答。此外,他有一种卓越的能力, 能够区别不同的甚至是关系紧密的微生物和分子。正因为如此,它有被成为特异性免疫,有时候也叫后天免疫,是为了强调这种强大的保护应答是因为(不断)接触而获得的。适应性免疫的主要成分是淋巴细胞和他们的分泌物比如抗体。诱发特异性免疫或者被淋巴细胞或抗体识别的外来物质被称为抗原。 Mechanisms for defending the host against microbes are present in some form in all multicellular organisms . These mechanisms constitute innate immunity The more specialized defense
mechanisms that constitute adaptive immunity are found in vertebrates only. Two functionally similar but molecularly distinct adaptive immune systems developed at different times in evolution. About 500 million years ago, jawless fish. such as lampreys and hagfish. developed a unique immune system containing diverse lymphocyte-like cells that may function like lymphocytes in more advanced species and even responded to immunization The antigen receptors on these cells were variable leucine-rich receptors that were capable of recognizing many antigens but were distinct from the antibodies and T cell receptors appeared later in evolution. Most of the ponents of the adaptive immune system, including lymphocytes with highly diverse antigen receptors, antibodies. specialized lymphoid tissues, evolved coordinately within a short time in jawed vertebrates (e. g. , sharks). about 360 million years ago. The immune system has bee increasingly specialized with evolution . 保护诉诸抵制微生物的机制在所有的多细胞生物中以某种形式存在着。这些机制构成了固有免疫。构成适应性免疫的更加特异的防御机制只有在脊椎动物身上才有。在进化过程中两种功能相似但是分子相异的适应性免疫系统在不同时期得到了发展。大约5亿年前,八目鳗和盲鳗这些无颚鱼进化了一种独一无二的免疫系统,
它有各种像淋巴细胞一样的细胞,能在更加高级的物种里像淋巴细胞一样发挥作用,甚至能对免疫应答。这些细胞上的抗原受体是多变的亮氨酸受体,能够识别许多的抗原,但是却和后来进化过程中出现的抗体和T细胞不同。适应性免疫系统的大多数成分,包括带有高度多样化抗原受体的淋巴细胞,抗体和特异的淋巴组织,是在3亿6千万年前在有颚脊椎动物(比如鲨鱼)中短时间里协调进化的。免疫系统也在进化过程中日益特异化。 Innate and adaptive immune responses are ponents of an integrated system of host defense in which numerous cells and molecules function cooperatively. The mechanisms of innate immunity provide effective initial defense against infections. However. many pathogenic microbes have evolved to resist innate immunity. their elimination requires the more powerful mechanisms of adaptive immunity .There are many connections between the Innate and adaptive immune systems. The innate immune response to microbes stimulates adaptive immune responses and influence nature of the adaptive responses Conversely. adaptive immune
responses often work by enhancing the protective mechanisms of innate immunity, making capable of effectively bating pathogenic microbes. 固有免疫和适应性免疫是宿主整个防御系统组成成分,无数的细胞和分子彼此协作。固有免疫的机制对感染提供早期的有效防御,然而,一些病原微生物已经进化到可以抵制固有免疫,消除他们需要更加强大的适应性免疫机制。固有免疫和适应性免疫有
千丝万缕的联系,对微生物的固有免疫应答会激发适应性免疫应答,影响适应性免疫的性质。反过来,适应性免疫应答常常通过加强固有免疫的保护机制是自己有能力和病原微生物有效的战斗。
unit7
受体 药理学研究化学物质对生物体形象的方方面面,当其用于缓解或治疗疾病时,称为药物。 大多数药物通过与生物体的受体结合产生药效。药物分子与受体之间的化学键通常可
Learn for practice
On campus, there are a special group of students. They live an ascetic monk’s life. They are reading endless fat books in the classroom while other peers having a lot of fun seeing a film with friends. They stay at a frowzy dissecting room all morning facing fragmentary and sickening dead bodies while other peers sit in on a class and fall asleep in the cosy atmosphere. They are reciting hundreds of clinical cases all night long while other peers celebrating for the graduation in the corner. These ascetic monks are our medical students.
After 5 to 7 or 8 years hard work on campus and several years’ internship in hospital, these poor students are allowed to working in a hospital with a meager salary. They work day and night,warding round, making medical orders, writing and discussing cases, performing an operation, making death certificate, birth records, contact higher authorities, explaining this or that to patients knowing nothing, having this or that meetings like a white-collar——to name just a few. The only similarity between life in college and hospital is busyness, endless busyness. Thanks for those hard university time, doctors can bear enormous pressure in hospital.
In fact, the biggest challenge when a student is thrown into a hospital is not
busy work. What makes us surprising and sad is that we don’t know the way to apply what we learn into practice. We know much about the ins and outs of a disease, because we were well trained in college, but we don’t know how to explain the disease to our patient, a lot of terms from our mouth making patients bored and doubtful. They may ment “this young doctor is just theoretical” afterwards. We learn a lot of
knowledge about human body, but when we are facing a bleeding surgical incision, we feel afraid and at a loss. Every nerve is important, every artery may bleed a good many when cut carelessly.
Doctors are busy and tired, but they are not respected by most people nowadays. The tense physician-patient relation makes it more difficult for doctor to practice their skills. Modern health care system makes physicians and patients far away from each other. However, we know nothing about how a hospital runs, not to mention the health-care system. Consequently, adapting to the plex and dangerous system is a big problem for our medical students.
We are enthusiastic and young students, we can’t allow the holy medical science and our dream destroyed by anything. But where are the solutions? What can we do to learn for practice? In my opinion, students and college should join efforts to solve it. For our students, we can’t only focus on knowledge in books. There are many things to learn for our work, and there are a variety of approaches to learn them. On campus, we should pay more concentration on what happens in hospital. In fact, each of us has a whole course teacher who works in a hospital or a
laboratory. Certainly, we are supposed to municate with him frequently. However, we always miss this valuable chance in the name of heavy study. Nowadays, we can approach the inter easily. Therefore, it’s possible and necessary for us to make full use of it. So, go to collect more information and ideas about career and what happens in the medical world, using the entrancing iPods,puters and the inter.
For the college, the course provided for us should be changed. Some course about
system thinking, quality improvement and patient safety should be added to the medical training. More systematic practice regarding to clinical skills must be carried on. We were allowed to hospitals during the pre-probation when we were studying in Zhuhai
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