醫(yī)學(xué)英語(yǔ)翻譯

1、Unit1The Human complex A Never failing Source of Wonderment “ In my view, ” wrote Thomas Jefferson in 1814 , “no knowledge can be more satisfactory to a man that of his own frame, its parts, their functions and actions. ” Distinguished thinkers before and since Jefferson have held this belief, but c

2、uriously, it is not one that the average person wholeheartedly shares. Mans attitude toward his own bodyhis single most precious possessionis decidedly ambivalent. At one and the same time he is fascinated by it and fearful of it, partly in echo of ancient taboos, partly in the conviction that the b

3、ody is too complicated to understand. “在我看來，”托馬斯杰佛遜于1814年寫道：“對(duì)人來說，沒有什么知識(shí)會(huì)比了解自身的架構(gòu)、部件、以及他們的功能和運(yùn)動(dòng)更能使他滿足?！痹诮芊疬d前后的杰出思想家均持有這個(gè)觀點(diǎn)，但激發(fā)人好奇心的是，這個(gè)觀點(diǎn)并不為普羅大眾所由衷地接受。人們對(duì)自己的身體（這個(gè)對(duì)他自身來說最為寶貴的財(cái)富）的態(tài)度其實(shí)是充滿矛盾的。一方面，人們對(duì)身體感到非常著迷，另一方面，卻又對(duì)其深感敬畏，這在一定程度上是受古代禁忌的影響，也在一定程度上反映了人們確信肉體過于復(fù)雜而難以理解。 The possible approaches to a study of

4、the body are legion. To the cynic, the body is no more than a tenement of clay; to the poet, a palace of the soul; to the physician, an all-too-ailing hulk. The psychiatrist sees it as a housing for the mind and personality. The geneticist sees it as a perpetuator of its own kind. The biologist sees

5、 it as an organism which can alter the future as a result of the experience of the past. 研究人體的方法可謂紛繁多樣。對(duì)憤世嫉俗者來說，人體賤如粘土陋室；對(duì)吟詩(shī)作賦者來說，人體尊如靈魂的宮殿；對(duì)內(nèi)科醫(yī)生來說，人體是脆弱多病的軀殼。精神病學(xué)家視其為理智和個(gè)性的居所。遺傳學(xué)家當(dāng)其為自我繁衍的機(jī)器。生物學(xué)家視其為能借過往的經(jīng)驗(yàn)來改變未來的生命體。 All the specialized scientific views of the body are valid. All, however, must start

6、 from the same premise: an awareness of the bodys basic structure and functionsits anatomy and physiology. And the bedrock principle of our present understanding of the body is that all living matter is composed of cells basically similar in structure and function. 所有有關(guān)人體的專業(yè)科學(xué)的觀點(diǎn)都是有依據(jù)的，然而，所有的這些都必須有同

7、一個(gè)前提：那就是對(duì)研究人體的基本結(jié)構(gòu)和功能的解剖學(xué)和生理學(xué)的認(rèn)識(shí)。我們對(duì)身體的了解的基本原則是，所有生物都是由結(jié)構(gòu)和功能基本相似的細(xì)胞構(gòu)成的。A Swarm of Tiny Specialists Studies of the cellwhat it is , what it does and how it reproduces itself have revealed it to be a fantastically complex world in itself. One of the major wonders of the cell is the disparity between i

8、ts minuteness and the prodigiousness of its activity. Each cell is so tiny that millions of them may be found in a half-inch cube of human body tissue. Yet each comprises an almost unimaginably busy chemical laboratory with a highly ordered division of labor. 關(guān)于細(xì)胞的研究細(xì)胞是什么，它是干什么的和如何復(fù)制的已經(jīng)表明細(xì)胞本身就是一個(gè)令人難

9、以置信的復(fù)雜世界。細(xì)胞的一大精妙之處在于其體積之微細(xì)與其活性之大之間的反差。每個(gè)細(xì)胞是如此渺小，以至于在一個(gè)半英寸立方體大小的人體組織中可能發(fā)現(xiàn)數(shù)以萬(wàn)計(jì)的細(xì)胞。然而，每個(gè)細(xì)胞都堪比一個(gè)繁忙到難以想象的并有著高度的分工的化學(xué)實(shí)驗(yàn)室。 The cell has two main parts: a nucleus, containing the genetic material deoxyribonucleic acid (DNA), and a surrounding semifluid cytoplasm. Bounding the cytoplasm is the cell membrane,

10、 which keeps the cell contents in and undesirable material out, yet permits passage of both proper nutrients and wastes. The nucleuscell headquartersgoverns the major activities of the cytoplasm; its finest hour, however, comes at reproduction time, when chromosomes containing DNA split. It is in th

11、e cytoplasm, that the cells day to day business is carried on. Each of its various components, or organelles, is a specialist of surpassing skill. One type breaks down the food given entry by the cell membrane and converts it into energy .Another provides the site for the synthesis of proteinalong w

12、ith reproduction, a major function of most cells. Another packages the manufactured protein for transport wherever needed in the body. 細(xì)胞有兩個(gè)主要部分：含有遺傳物質(zhì)脫氧核糖核酸（DNA）的細(xì)胞核，以及周圍呈半流質(zhì)的細(xì)胞質(zhì)。包圍著細(xì)胞質(zhì)的是細(xì)胞膜，它包含著細(xì)胞內(nèi)容物,并將不需要的物質(zhì)隔離在外，然而它允許營(yíng)養(yǎng)物質(zhì)和代謝廢物通過。細(xì)胞核細(xì)胞的控制中心調(diào)控細(xì)胞質(zhì)的主要活動(dòng)；然而，它最美妙的時(shí)刻是當(dāng)細(xì)胞分裂時(shí)，包含DNA的染色體分裂繁殖。細(xì)胞日復(fù)一日的工作是在細(xì)胞質(zhì)中

13、完成的。各種組件或細(xì)胞器，都是一個(gè)個(gè)卓越的技術(shù)專家。其中一個(gè)功能是分解從細(xì)胞膜進(jìn)入細(xì)胞的營(yíng)養(yǎng)物質(zhì)，并將其轉(zhuǎn)化成能量。另一個(gè)功能是提供蛋白質(zhì)合成的場(chǎng)所伴隨著細(xì)胞復(fù)制的全過程，這是大多數(shù)細(xì)胞的主要功能。再一個(gè)功能是加工包裝制造的蛋白質(zhì) ，并將其運(yùn)輸?shù)缴眢w所需的各個(gè)部位。 To operate efficiently, the cell thus requires specific help from the body as a whole: food to provide raw material for the release of energy, oxygen to help break do

14、wn the food, water to transport inorganic substances like calcium and sodium. Once its needs are satisfied, the cell itself provides the intricate mechanism for maintaining the balance essential to keep it in kilterin short, to keep the body alive and healthy. 為了工作的高效運(yùn)行，細(xì)胞需要得到身體的特定的幫助，總的來說：食物提供可釋放能量

15、的原材料，氧氣幫助分解食物，水用于運(yùn)輸無機(jī)物，比如鈣、鈉。一旦這些需要得到滿足，細(xì)胞自身就會(huì)通過錯(cuò)綜復(fù)雜的機(jī)制，來保持正常運(yùn)作所必須的平衡確使身體處于正常狀態(tài)簡(jiǎn)而言之，就是保持身體的活力和健康。 Cells share certain common characteristics, but most of the body's cells develop specialized features and abilities. The cells that form bone collect calcium salts; these cells are locked together i

16、n solid chunks, immobile. By contrast, the white cells of the blood, which fight off invading bacteria, roam freely about the body. Other cells make special chemicals for the body's usethe hormones produced in the endocrine glands, or the digestive enzymes poured into the intestine from the panc

17、reas. Still other cells form the incredibly thin membranes in the lung or kidney that permit the filtering or exchange of dissolved body fuels and wastes.細(xì)胞擁有一定的共性，但是大部分的人體細(xì)胞具有他們特化的特征和功能。那些構(gòu)成骨的細(xì)胞能沉積鈣鹽，這些細(xì)胞連鎖成堅(jiān)固而無活動(dòng)能力的塊狀固體。相比之下，血液中那些可以抵抗細(xì)菌侵略的白細(xì)胞，卻能在身體內(nèi)自由流動(dòng)。某些細(xì)胞能產(chǎn)生特殊的化學(xué)物質(zhì)供身體使用如內(nèi)分泌腺產(chǎn)生的激素，由胰腺分泌并進(jìn)入腸道的消化酶

18、。還有些細(xì)胞在肺或腎臟形成非常薄的膜，使其能夠過濾或交換已被溶解的身體燃料和廢物。 According to their particular features and their intended functions, cells form different types of tissue: bone, muscle, blood, nerve tissue, connective tissue and epithelium. The cells that make up each of these are not identical, but belong together by rea

19、son of underlying similarities. 根據(jù)它們各自的特點(diǎn)和所要求的功能，細(xì)胞形成不同種類的組織：骨、肌肉、血液、神經(jīng)、結(jié)締組織和上皮組織。構(gòu)成這些組織的細(xì)胞是不同的，但因潛在的相似之處而同屬一類。 For example, the cells of bowel muscle are rounder and shorter than the long, spindly cells of leg muscle, yet both kinds contract forcefully when stimulated by a chemical or electrical im

20、pulse. The cells that make up bone tissue differ sufficiently to make brittle bone in one place and spongy, resilient cartilage in another, yet all store the salts which give bone its calcified structure. The loose network of cells that supports the fatty padding under the skin and the dense capsule

21、 of cells that holds the knee joint in place are both forms of connective tissue. All nerve cells, varied as they may be, receive and conduct electrochemical impulses. All blood cell, varied as they may be, float freely in a circulating fluid, plasma. 例如，腸道的肌纖維比腿部細(xì)長(zhǎng)的肌纖維更圓、更短，但是當(dāng)這兩種細(xì)胞都受到化學(xué)或電刺激時(shí)，它們都會(huì)發(fā)

22、生強(qiáng)有力地收縮。構(gòu)成骨組織的細(xì)胞是有相當(dāng)程度的不同，它們可以在一處形成脆骨，而在另一處形成疏松而有彈性的軟骨；然而，所有的細(xì)胞能儲(chǔ)存鈣鹽，使骨成為鈣化的結(jié)構(gòu)。支撐皮下脂肪的疏散網(wǎng)狀細(xì)胞和維持膝關(guān)節(jié)在恰當(dāng)位置的密集膠囊狀細(xì)胞，都共同參與構(gòu)成了結(jié)締組織。盡管可能有所不同，所有的神經(jīng)細(xì)胞都能接受并傳導(dǎo)電化學(xué)沖動(dòng)；盡管可能有所不同，所有的血細(xì)胞都能在循環(huán)流體血漿中自由地漂浮。 The most versatile cells are those of the various kinds of epithelium. Forming the bodys external coatingthe skine

23、pithelial cells protect things inside from things outside. They also form the lining of the mouth, stomach and bowel, the inner surface of blood vessels, and the membranes that permit the lungs to breathe and the kidneys to excrete. Over the cornea of the eye they become a sort of transparent windsh

24、ield, to permit the free entry of light to the retina. Other epithelial cells secrete a protective mucus to keep intestines, lungs and nasal passages from drying out. Still others manufacture powerful hormones that regulate the bodys chemical reactions. 最萬(wàn)能的細(xì)胞是各種各樣的上皮細(xì)胞。它們共同構(gòu)成人體的外套皮膚，上皮細(xì)胞保護(hù)皮膚里面的物質(zhì)不受

25、外界侵害。它們還構(gòu)成口腔、胃黏膜、腸黏膜、血管內(nèi)皮和參與肺呼吸以及腎排泄的膜。 覆布于眼角膜上的上皮細(xì)胞，它們變成一種透明的擋風(fēng)玻璃，使得光束自由地進(jìn)入到視網(wǎng)膜。其他的上皮細(xì)胞分泌保護(hù)性的粘液保持腸、肺和鼻腔不至于變干燥。還有一些上皮細(xì)胞能夠產(chǎn)生高效能的激素來調(diào)節(jié)人體化學(xué)反應(yīng)。Interlock and Overlap The tissues comprise the structural materials of the bodys organ systems. These, in turn, may be compared to a number of corporations with

26、interlocking directorates. Indeed the interdependence of the organ systems has led to some disagreement over how many there are. The venerable Grays Anatomyused by medical students for more than 100 yearslists 10 systems: nervous, digestive, respiratory, vascular, urogenital, endocrine, skeletal, mu

27、scular, joints and external covering. Other authorities categorize joints and bones together because they are so closely related, or separate the sense organs from the nervous system, or lump all the internal organs respiratory, digestive, endocrine and urogenitalunder the resounding title of splanc

28、hnological system. 人體器官系統(tǒng)的物質(zhì)結(jié)構(gòu)由組織組成。換言之，這就像互相之間交叉任職的董事的若干公司。事實(shí)上這些相互依賴的器官系統(tǒng)在他們數(shù)量多少的問題上也曾引發(fā)了一些爭(zhēng)論。備受推崇的Gray解剖學(xué)-曾被被醫(yī)學(xué)生使用了上百年的時(shí)間-列舉出了十個(gè)系統(tǒng)：神經(jīng)系統(tǒng)，消化系統(tǒng)，呼吸系統(tǒng)，血管系統(tǒng)，泌尿生殖系統(tǒng)，內(nèi)分泌系統(tǒng)，骨骼系統(tǒng)，肌肉系統(tǒng)，關(guān)節(jié)和皮膚系統(tǒng)。而另一些權(quán)威人士則因關(guān)節(jié)和骨頭是密不可分的而將他們歸為一類，或是將感覺器官?gòu)纳窠?jīng)系統(tǒng)分離出來，或是將所有的內(nèi)臟器官-呼吸器官，消化器官，內(nèi)分泌器官以及泌尿器官混在一塊，冠以內(nèi)臟系統(tǒng)這一聲勢(shì)浩大的名稱。 Far more import

29、ant than their labels is the fact that the systems interact; the breakdown of one can damage or destroy the others. Ideally, of course, all systems would do their jobs perfectly all the time. Unfortunately, nature permits no such perfection. All of them suffer from malfunctions at one point or anoth

30、er. The wonder is that breakdowns are the exception rather than the rule. 然而比給他們的命名更為重要的是他們各個(gè)系統(tǒng)之間會(huì)相互影響這個(gè)事實(shí)，其中一個(gè)系統(tǒng)的衰弱可以損害或毀滅其他系統(tǒng)。當(dāng)然，理想狀態(tài)下，所有的系統(tǒng)都是能一直完美地執(zhí)行他們的任務(wù)的。而不幸的是，自然狀態(tài)下是不可能出現(xiàn)這么完美的情況的。在所有系統(tǒng)當(dāng)中，他們總會(huì)因這個(gè)方面或那個(gè)方面的故障而受到損害。神奇的是，出現(xiàn)故障倒是例外而不是常規(guī)情況 Within the healthy body itself there is no absolute criterion f

31、or "normal". Variations occur not only between individuals, but within the individual himself, sometimes from hour to hour, depending on his activity at the time. Doctors privately joke that even a baboon could get through medial school if he learned to say, with enough profundity, "I

32、t varies." One of the practitioners major headaches is to determine whether a patients condition reflects an actual illness or merely a variation within a broad range of normal. The breadth of this range may be indicated by a few statistics. The weight of the healthy heart is considered to be a

33、nywhere between 240 and 360 grams; the weight of the healthy liver, between 1,000 and 2,000 grams; the level of sugar in the blood, between 70 and 130 milligrams.在健康的人體內(nèi)對(duì)于“正常”也沒有確切的標(biāo)準(zhǔn)可言。變化不僅僅發(fā)生在個(gè)體之間，也可以發(fā)生在個(gè)體內(nèi)部，有時(shí)候每個(gè)小時(shí)都不同，這要看他們當(dāng)時(shí)的運(yùn)動(dòng)狀態(tài)。醫(yī)生私下開玩笑說，即使是一個(gè)狒狒，它也可以在醫(yī)學(xué)院校畢業(yè)，前提是他學(xué)會(huì)很深沉地說“因人而異”。令從醫(yī)者最頭痛的問題之一就是要確認(rèn)一個(gè)

34、人的情況是真正生病了還是處于正常的變化范圍之中。有些范圍內(nèi)的波動(dòng)可能是已經(jīng)被一些統(tǒng)計(jì)資料所確認(rèn)的。健康的心臟重量范圍是240360g，健康的肝臟重量在10002000g之間，血糖濃度水平是70130mg。Unit 2Reading AHuman Anatomy The human body is a remarkably complex and efficient machine. It takes in and absorbs oxygen through the respiratory system. Then the oxygen-enriched blood is distribute

35、d through the cardiovascular system to all tissues. The digestive system converts digestible food to energy and disposes of the rest. The skeletal-muscular system gives form to the body. And covering almost the entire mass is the skin, the largest organ of the body. The science of the structure of t

36、his complicated” machine” is called anatomy.人體是一個(gè)非常復(fù)雜并且高效的機(jī)器。它通過呼吸系統(tǒng)吸入并且吸收氧氣。然后這富含氧的血液通過心血管系統(tǒng)被分布到所有的組織。消化系統(tǒng)將能消化的食物轉(zhuǎn)變成能量并且將剩余的廢物排出。骨骼-肌系統(tǒng)組成了人體的輪廓。全身最大的器官皮膚,幾乎覆蓋整個(gè)軀體。這門研究機(jī)體復(fù)雜構(gòu)造的科學(xué)被稱為“解剖學(xué)” One of the major systems is the skeletal-muscular system. The body is supported and given shape by this structure,

37、 consisting of more than 200 bones and the muscles and tendons which are connected to them. They are strong but can bend at their joins. They also serve as a shield, protecting the vital internal organs from injury. 主要的系統(tǒng)之一是骨骼-肌系統(tǒng)。人體由這個(gè)結(jié)構(gòu)作支撐并構(gòu)成形態(tài)，這一結(jié)構(gòu)由200多塊骨和肌肉及與之相連的肌腱組成。它們很堅(jiān)固但是能夠通過彎曲關(guān)節(jié)。它們也能像防護(hù)物一樣，保

38、護(hù)內(nèi)部重要的器官免受傷害。 Bones are as strong as steel but much lighter and more flexible. They are composed of minerals, organic matter, and water, held together by a cement-like substance called collagen, and are filled with red and yellow bone marrow. The red marrow produces the red blood cells used througho

39、ut the body to transport oxygen, while the yellow marrow consists of fat cells. A tough membrane called the periosteum covers most of the bone surface and allows bones to be nourished by blood. 人體的骨骼像鋼鐵一樣堅(jiān)韌但是骨骼更輕更柔韌。這些骨骼由礦物質(zhì)，有機(jī)物，水構(gòu)成-它們通過一種被稱為膠原的類似結(jié)合劑的物質(zhì)連結(jié)起來，并且充滿了紅骨髓和黃骨髓。紅骨髓產(chǎn)生一種能夠運(yùn)輸氧氣到達(dá)全身各處的血紅細(xì)胞，然而黃骨

40、髓由脂肪細(xì)胞組成。有一種堅(jiān)韌的膜被稱為骨膜，它覆蓋了大部分骨的表面，使骨頭能得到血液的滋養(yǎng)。 A major bone structure in the body is the vertebral (spinal) column. It runs up and down the back and protects the spinal cord, where many of the major nerves are located. It is composed of bony vertebrae which are held together by ligament of connectiv

41、e tissue and separated from each other by spinal discs. At the top of the vertebral column is the skull, which surrounds and protects the brain. Attached to the vertebral column below the neck are the 12 pairs of ribs, comprising the rib cage. At the bottom is the sacrum, which connects the vertebra

42、l column to the pelvis. Bones are united by joints and held together by ligaments. 身體中一個(gè)主要的骨骼結(jié)構(gòu)是脊柱。它貫穿人體背部并且保護(hù)脊髓，有很多重要的神經(jīng)位于這里。脊柱是由屬于結(jié)締組織的韌帶連接起來的椎骨組成的，并且相鄰椎骨由椎間盤分隔開。在脊柱的頂部是顱骨，顱骨包裹并且保護(hù)腦。在頸部以下連著脊柱的是12對(duì)肋骨，共同構(gòu)成了胸廓。脊柱的底部是骶骨，骶骨把脊柱和骨盆連接在一起。骨骼通過關(guān)節(jié)聯(lián)合并且通過韌帶連結(jié)。 Muscles are special fibrous tissues found througho

43、ut the body. They control movement and many organic functions by contracting in response to nerve signals. Skeletal muscles are called voluntary because they can be consciously controlled. They are attached to bones by tough fibrous tissues called tendons. Other muscles, such as the stomach muscled

44、and the heart, are involuntary and are operated automatically by the central nervous system.肌肉是遍布身體的特殊纖維組織。它們通過收縮來回應(yīng)神經(jīng)信號(hào)從而控制運(yùn)動(dòng)和許多器官功能. 骨骼肌能被意識(shí)控制，所以稱為隨意肌。它們通過一個(gè)叫肌腱的結(jié)實(shí)纖維組織緊緊附著于骨上。其他肌肉，例如胃肌和心肌，都是非隨意肌，由中樞神經(jīng)系統(tǒng)控制，自動(dòng)運(yùn)作. The most important muscles in the body is the heart. Without the heart and its cardiova

45、scular (circulatory) system, human life would not be possible. The heart is roughly the size of two fists. It contracts at an average rate of 72 times per minute or nearly 38,000,000 times a year. These rhythmic contractions are called the pulse rate and can be felt in the radial artery of the wrist

46、. 心肌是人體最重要的肌肉，沒有心肌和它的心血管循環(huán)系統(tǒng)，人類將不可能生存。心臟大概兩個(gè)拳頭那么大，平均每分鐘收縮72次或接近38000000次每年。這種有節(jié)奏的收縮稱之為脈搏, 并且可以在手腕的橈動(dòng)脈處感覺到。 The human heart consists of four chambers ，two atria and two ventricles .Each is made up of several layers of cardiac muscles arranged in circles and pirals. During the contraction phase, calle

47、d the systole, oxygenated blood is pumped out of the left ventricle into the aorta and from there through the arteries to all organs of the body. Carbon dioxide, a waste product of this process ,is collected in the blood. The blood is passed back to the right atrium through the veins and the vena ca

48、va during the diastole (or relaxation) period of the heart. From there, it is pumped into the right ventricle and to the pulmonary artery to be sent to the lungs where carbon dioxide is removed and oxygen is added.人的心臟由四個(gè)腔室組成, 兩個(gè)心房和兩個(gè)心室, 每個(gè)腔都是由許多層心肌環(huán)繞，盤旋排列而成。（心臟）在收縮階段，被稱為收縮期，富含氧的血液從左心室泵出進(jìn)入主動(dòng)脈，然后從那里通

49、過動(dòng)脈運(yùn)送到全身所有的器官。二氧化碳是這個(gè)過程中產(chǎn)生的廢物，通過血液收集。血液在心臟舒張期通過靜脈和腔靜脈回流到右心房。從那，血液被泵入右心室并通過肺動(dòng)脈被送到肺部，在那二氧化碳被移除，氧氣被加入。 The rest of the system consists of arterioles (small arteries), venules (small veins), and capillaries, the smallest of blood vessels. In total, there are more than 70000 miles of blood vessels in the

50、 human body!這個(gè)（心臟）系統(tǒng)的其余部分則是由小動(dòng)脈，小靜脈及最微小的血管毛細(xì)血管構(gòu)成，總的來說，人體中的血管長(zhǎng)度遠(yuǎn)遠(yuǎn)超過70000英里！ The cardiovascular system also carries hormones which are secreted by glands of the endocrine system directly into the bloodstream. These hormones control many functions of the body. The thyroid gland, for example, secrets th

51、yroxin ,which controls the rate at which energy is produced（the metabolic rate）.心血管系統(tǒng)也參與運(yùn)輸一些由內(nèi)分泌系統(tǒng)的腺體分泌且直接進(jìn)入血漿的激素。這些激素控制身體的許多功能。例如，甲狀腺分泌甲狀腺素，這種激素控制著能量產(chǎn)生的速度（代謝率）。 The respiratory system starts at the nasal passage, where air is breathed in during inspiration. There the air is filtered and its tempera

52、ture regulated. It passes through the larynx and trachea into the bronchi and bronchioles, and ends in little air pockets called alveoli within the lungs. The used blood is cleansed of carbon dioxide, which is expelled in the process known as expiration. The cleansed blood is then oxygenated and red

53、istributed along the circulatory system. The entire process is called respiration and occurs at the rate of about 16 to 20 times per minute. 呼吸系統(tǒng)始于鼻腔通道，即吸氣時(shí)空氣進(jìn)入的地方。在那里（鼻腔）空氣被過濾，溫度被調(diào)節(jié)。然后，空氣通過喉和氣管進(jìn)入支氣管和細(xì)支氣管，最后進(jìn)入肺部被稱作肺泡的小氣泡里面。被用過的血液清除二氧化碳并通過呼氣過程排出。凈化后的血液隨后被氧化并且隨著循環(huán)系統(tǒng)被重新分配。這整個(gè)過程稱為呼吸，它發(fā)生的頻率在每分鐘16到20次之間。

54、The largest organ in the body is the outer covering called Skin.(the average man about 20 square feet of it. ) The skin plus its associated structures (hair, nails, sebaceous and sweat glands, and specialized sensory receptors that enable the body to be aware of touch, cold, heat, pain, and pressure

55、) make up the integumentary system. Skin protects the body from microbes and other impurities, prevents the loss of body fluids, and regulates body temperature. Three layers of tissue make up the skin-the epidermis, the dermis, and the subcutis (subcutaneous layer) The epidermis is in constant growt

56、h, with its outer layer of dead cells continuously being replaced as new cells are formed in the lower layer. Hair, fingernails, and toenails are specialized forms of epidermis. The coloring pigment called melanin is also found in the epidermis. The middle layer (or dermis) is the location for two m

57、ain types of glands-sweat glands and oil glands. The innermost subcutis contains fat cells, blood vessels, and nerves. 人體最大的器官就是包裹在人體表層的皮膚（一般人的皮膚面積平均約為20平方英尺）。皮膚加上與之相關(guān)的結(jié)構(gòu)（頭發(fā)，指甲，皮脂腺和汗腺，以及專門能使身體感受觸摸，冷，熱，痛苦和壓力的感受器）共同組成了皮膚系統(tǒng)。皮膚能保護(hù)機(jī)體免受微生物和其他雜質(zhì)的傷害，防止體液流失，及調(diào)節(jié)體溫。 三層組織組成皮膚-表皮，真皮，和皮下組織(皮下層)。表皮是在不斷增長(zhǎng)的，在表皮下層新形成

58、的細(xì)胞會(huì)不斷地替代外層死亡的細(xì)胞。頭發(fā)，指甲和腳趾甲都是表皮的特化形式。在表皮中也發(fā)現(xiàn)了被稱為黑色素的著色色素。中間層（或真皮層）是皮膚的兩種主要腺體，汗腺和皮脂腺的所在地。 最里面的皮下組織包含脂肪細(xì)胞，血管和神經(jīng)。 Another major body complex is the digestive system, which processes the food so that it can be used for energy. The process begins in the mouth, where food is chopped and crushed by the teet

59、h. In the mouth, saliva, excreted by the salivary glands, provides enzymes that help to break down the foods carbohydrates. This taking of food into the body for digestion is called ingestion. 另一個(gè)主要的身體復(fù)合體是消化系統(tǒng)，該系統(tǒng)對(duì)食物進(jìn)行加工處理，以便食物能被作為能量使用。該過程開始于口腔，食物被牙齒嚼碎和粉碎。在口腔里，由唾液腺分泌的唾液提供的酶有助于分解食物中的碳水化合物。這種為了消化而獲取食物進(jìn)入身體稱為攝入。 After food has been chewed, it passes through the esophagus into the stom