醫(yī)學(xué)專業(yè)英語(yǔ)翻譯及答案

1、Chapter 1 Passage 1 Human BodyIn this passage you will learn:1. Classification of organ systems2. Structure and function of each organ system3. Associated medical terms To understand the human body it is necessary to understand how its parts are put together and how they function. The study of the b

2、odys structure is called anatomy; the study of the bodys function is known as physiology. Other studies of human body include biology, cytology, embryology, histology, endocrinology, hematology, immunology, psychology etc.了解人體各部分的組成及其功能，對(duì)于認(rèn)識(shí)人體是必需的。研究人體結(jié)構(gòu)的科學(xué)叫解剖學(xué)；研究人體功能的科學(xué)叫生理學(xué)。其他研究人體的科學(xué)包括生物學(xué)、細(xì)胞學(xué)、胚胎學(xué)、組

3、織學(xué)、內(nèi)分泌學(xué)、血液學(xué)、遺傳學(xué)、免疫學(xué)、心理學(xué)等等。 Anatomists find it useful to divide the human body into ten systems, that is, the skeletal system, the muscular system, the circulatory system, the respiratory system, the digestive system, the urinary system, the endocrine system, the nervous system, the reproductive syst

4、em and the skin. The principal parts of each of these systems are described in this article.解剖學(xué)家發(fā)現(xiàn)把整個(gè)人體分成骨骼、肌肉、循環(huán)、呼吸、消化、泌尿、內(nèi)分泌、神經(jīng)、生殖系統(tǒng)以及感覺(jué)器官的做法是很有幫助的。本文描繪并闡述了各系統(tǒng)的主要部分。The skeletal system is made of bones, joints between bones, and cartilage. Its function is to provide support and protection for the

5、soft tissues and the organs of the body and to provide points of attachment for the muscles that move the body. There are 206 bones in the human skeleton. They have various shapes - long, short, cube - shaped, flat, and irregular. Many of the long bones have an interior space that is filled with bon

6、e marrow, where blood cells are made.骨骼系統(tǒng)由骨、關(guān)節(jié)以及軟骨組成。它對(duì)軟組織及人體器官起到支持和保護(hù)作用，并牽動(dòng)骨胳肌，引起各種運(yùn)動(dòng)。人體有206根骨頭。骨形態(tài)不一，有長(zhǎng)的、短、立方的、扁的及不規(guī)則的。許多長(zhǎng)骨里有一個(gè)內(nèi)層間隙，里面充填著骨髓，這即是血細(xì)胞的制造場(chǎng)所。A joint is where bones are joined together. The connection can be so close that no movement is possible, as is the case in the skull. Other kinds

7、of joints permit movement: either back and forth in one plane - as with the hinge joint of the elbow - or movement around a single axis - as with the pivot joint that permits the head to rotate. A wide range of movement is possible when the ball - shaped end of one bone fits into a socket at the end

8、 of another bone, as they do in the shoulder and hip joints. 關(guān)節(jié)把骨與骨連接起來(lái)。顱骨不能運(yùn)動(dòng)，是由于骨與骨之間的連接太緊密。但其它的關(guān)節(jié)可允許活動(dòng)，如一個(gè)平面上的前后屈伸運(yùn)動(dòng)，如肘關(guān)節(jié)；或是繞軸心旋轉(zhuǎn)運(yùn)動(dòng)，如樞軸點(diǎn)允許頭部轉(zhuǎn)動(dòng)。如果一根骨的球形末端插入另一根骨的臼槽里，大輻度的運(yùn)動(dòng)（如肩關(guān)節(jié)、髖關(guān)節(jié)）即成為可能。Cartilage is a more flexible material than bone. It serves as a protective, cushioning layer where bones come t

9、ogether. It also connects the ribs to the breastbone and provides a structural base for the nose and the external ear. An infants skeleton is made of cartilage that is gradually replaced by bone as the infant grows into an adult.軟骨是一種比一般骨更具韌性的物質(zhì)。它是骨連結(jié)的保護(hù)、緩沖層。它把肋骨與胸骨連結(jié)起來(lái)，也是鼻腔與內(nèi)耳的結(jié)構(gòu)基礎(chǔ)。一個(gè)嬰兒的骨骼就是由軟骨組成，然

10、后不斷生長(zhǎng)、骨化，使嬰兒長(zhǎng)大成人。The muscular system allows the body to move, and its contractions produce heat, which helps maintain a constant body temperature. Striated muscles can be consciously controlled. The ends of these muscles are attached to different bones by connective tissue bands so that when the mus

11、cle contracts, one bone moves in relation to the other. This makes it possible to move the whole body, as when walking, or to move just one part of the body, as when bending a finger. Contractions of the heart and smooth muscles are not under conscious control. Smooth muscles are found in the walls

12、of organs such as the stomach and the intestines and serve to move the contents of these organs through the body.肌肉系統(tǒng)使軀體運(yùn)動(dòng)，肌肉收縮產(chǎn)生的熱有助于維持一個(gè)恒定的體溫。人體能夠有意識(shí)地控制條紋肌。結(jié)締組織使肌肉末端附著于不同的骨面上，所以當(dāng)肌肉收縮時(shí)，兩骨彼此靠近而產(chǎn)生運(yùn)動(dòng)。這也就使整個(gè)人體可以運(yùn)動(dòng)起來(lái)，如走路，運(yùn)動(dòng)軀體某個(gè)部位，如彎曲手指。心臟收縮和平滑肌收縮就不是被意識(shí)所控制的。器官壁內(nèi)層的平滑肌，如胃腸壁的平滑肌把胃腸中的物質(zhì)運(yùn)送到全身。The circulatory

13、system. All parts of the body must have nourishment and oxygen in order to function and grow, and their waste products must be removed before they accumulate and poison the body. The circulatory system distributes needed materials and removes unneeded ones. It is made up of the heart, blood vessels,

14、 and blood, which together make up the cardiovascular system. The blood is also part of the bodys defense system. It has antibodies and white blood cells that protect the body against foreign invaders. 循環(huán)系統(tǒng)：機(jī)體的所有部分需要營(yíng)養(yǎng)物質(zhì)和氧氣來(lái)使之發(fā)揮功能和生長(zhǎng)，也需要在這些器官所產(chǎn)生的廢物積聚而危害生命之前將其排除。循環(huán)系統(tǒng)運(yùn)送有用物質(zhì)，排泄廢物。心血管系統(tǒng)是循環(huán)系統(tǒng)的組成之一；心血管系統(tǒng)包

15、括心臟、血管及血液。血液也是機(jī)體防御系統(tǒng)的一個(gè)部分，血液中有抗體及白細(xì)胞來(lái)防止機(jī)體受到外來(lái)的侵襲。 The heart is a muscle that is divided into two nearly identical halves: one half receives blood from the lungs and sends it to the rest of the body, the other half sends blood that has traveled through the body back to the lungs. When the heart muscl

16、e contracts, the blood is forced out into arteries and enters small capillaries. Blood returns to the heart through veins. 心臟是一塊被分為幾乎對(duì)等兩半的肌肉。一半吸收來(lái)自肺部的血液，并將血液運(yùn)送到機(jī)體的其余部位，另一半使流經(jīng)全身的血液回流人肺。心臟收縮時(shí)，動(dòng)脈把全身血液輸送到毛細(xì)血管。靜脈輸送血液返回心臟。 Also functioning in circulation is the lymphatic system. Some of the fluid that sur

17、rounds cells does not reenter the blood vessels directly. This fluid, called lymph, returns to the heart by way of another system of channels - the lymph vessels. Lymph nodes along these vessels filter the fluid before it reenters the blood. The spleen is a large lymphatic organ that filters the blo

18、od. 淋巴系統(tǒng)也是循環(huán)系統(tǒng)的一個(gè)組成部分。一些細(xì)胞周圍的體液不是直接回流入血管通道，這種體液叫淋巴液，它是流經(jīng)另一個(gè)管道系統(tǒng)淋巴管而回流人心臟。沿淋巴管的淋巴結(jié)將淋巴液過(guò)濾，過(guò)濾后再回流人血液。脾是一個(gè)過(guò)濾血液的大淋巴器官。 The respiratory system takes in oxygen from the air and expels carbon dioxide and water vapor. Air enters the nose and mouth and travels through the larynx, and trachea. The trachea divi

19、des to enter each of the two lungs and then divides more than 20 times to form a very large number of small air spaces. Oxygen from the air enters the blood through capillaries in the walls of these air spaces, and the blood release carbon dioxide into the air spaces to be exhaled. 呼吸系統(tǒng)從空氣中攝取氧氣，并將二氧

20、化碳、水蒸氣排出體外?？諝饨?jīng)鼻腔、口腔人喉管、氣管。氣管分成左右支氣管，各連結(jié)左右肺，左右支氣管再分枝20多次，在終端形成大量微小的肺泡。從空氣攝取的氧氣流經(jīng)這些肺泡壁內(nèi)的毛細(xì)血管流入血液，血液再經(jīng)肺泡把釋放出的二氧化碳排出體外。 The digestive system consists of a tube extending from the mouth to the anus. In it, food and fluids are taken in, moved through the body, and broken down into small molecules that are

21、 absorbed into the circulatory system. This breakdown, known as digestion, is both a mechanical and a chemical process.消化系統(tǒng)是一個(gè)從口腔直到肛門的管道。食物和液體在消化道里被吸收，在腸道里移動(dòng)時(shí)，被分解成小分子物質(zhì)后再進(jìn)入循環(huán)系統(tǒng)。這種分解，即消化，是一個(gè)機(jī)械過(guò)程，也是一個(gè)化學(xué)過(guò)程。 Food enters through the mouth, where chewing and saliva start to break it up and make it easier

22、to swallow. Next, the food travels down through the esophagus to the stomach. Contractions of the stomachs muscular wall continue to break down the food mechanically, and chemical digestion continues when acid and enzymes are secreted into the stomach cavity. 食物進(jìn)入口腔里，咀嚼和唾液開(kāi)始將食物粉碎，使之便于吞咽。接著，食物經(jīng)食管人胃。胃

23、肌壁的收縮繼續(xù)機(jī)械化地分解食物，而當(dāng)酸和酶分泌入胃腔時(shí)，化學(xué)性消化開(kāi)始。The liquified food gradually passes into the small intestine. In the first part of the small intestine, called the duodenum, enzymes from the pancreas are added. These enzymes complete the chemical breakdown of the food. The digestion of fat is aided by bile, whic

24、h is made in the liver and stored in the gall bladder. The small intestine of an adult is about 21 feet (6.4 meters) long. Most of its length is devoted to absorbing the nutrients released during these digestive activities. 液體化食物逐漸進(jìn)入小腸。小腸的起始部分叫十二指腸，胰腺分泌的酶輔助食物消化。這些酶完成食物的化學(xué)分解。肝臟分泌的膽汁貯存在膽囊內(nèi)，膽汁有助于脂肪消化。一

25、個(gè)成年人的小腸有21英尺（6.4米）長(zhǎng)。小腸的大部分腸段用來(lái)吸收消化過(guò)程中釋放的營(yíng)養(yǎng)物質(zhì)。 The liquid remainder of the food enters the large intestine, or colon, which is about 12 feet (3.7 meters) long. It is more than twice as wide as the small intestine. In the large intestine most of the fluid is absorbed, and the relatively dry residues a

26、re expelled. 液狀的剩余食物進(jìn)入大腸，或結(jié)腸，它大約有12英尺（3.7米）長(zhǎng)。大腸是小腸的兩倍多寬。大部分液體在大腸內(nèi)被吸收，相對(duì)干化的殘余物被排出體外。 The urinary system maintains normal levels of water and of certain small molecules such as sodium and potassium in the body. It does this by passing blood through the kidneys, two efficient filtering organs that get

27、rid of any excess of various molecules and conserve those molecules that are in short supply. 泌尿系統(tǒng)維持水分及體內(nèi)某些小分子物質(zhì)，如鈉、鉀的正常水平。身體是通過(guò)讓腎過(guò)濾血液來(lái)做到這一點(diǎn)的。腎是兩個(gè)有效的過(guò)濾器官，它濾出各種多余的小分子物質(zhì)，保留那些供應(yīng)不足的小分子物質(zhì)。 The fluid that leaves the kidneys, known as urine, travels through a tube called the ureter to the bladder. The blad

28、der holds the urine until it is voided from the body through another tube, the urethra. 從腎流出的液體，即尿，通過(guò)輸尿管人膀胱。膀胱起貯存尿液的作用，直到尿經(jīng)膀胱另一端的管道排出。 The endocrine system. The two systems that control body activities are the endocrine system and the nervous system. The former exerts its control by means of chemica

29、l messengers called hormones. Hormones are produced by a variety of endocrine glands, which release the hormones directly into the blood stream. 內(nèi)分泌系統(tǒng)。內(nèi)分泌和神經(jīng)是調(diào)控機(jī)體活動(dòng)的兩個(gè)系統(tǒng)，前者依靠其化學(xué)信使激素發(fā)揮作用。激素是由各種內(nèi)分泌腺體制造，并直接被釋放入血流 A major gland is the pituitary, which is located under the brain in the middle of the head

30、. It produces at least eight hormones, which affect growth, kidney function, and development of the sex organs. Because some of the pituitarys hormones stimulate other glands to produce their own hormones, the pituitary called the master gland. 腦垂體是一個(gè)主要腺體，它位于頭中部腦下方。它至少分泌八種激素，這些激素對(duì)人體生長(zhǎng)、肝功能及性器官發(fā)育有影響。因

31、為腦垂體分泌的一些激素促進(jìn)其他腺體分泌激素，所以腦垂體是主要腺體。 Another gland, the thyroid, is located between the collar bones. Its hormone controls the rate of the bodys metabolism. The sex organs (ovaries end testes) make the sex cells and also make hormones that control certain characteristics of males and females. Located o

32、n top of each kidney is the adrenal gland, which produces cortisone and adrenaline. The pancreas produces not only digestive enzymes but also 3 insulin and glucagon, which control the bodys use of sugar and starches. 另一個(gè)腺體，甲狀腺，位于鎖骨之間。甲狀腺激素調(diào)控著機(jī)體新陳代謝的速度。性器官（卵巢、睪丸）分泌性細(xì)胞和性激素，這些激素控制著男性和女性的某些特征。每邊腎上方是腎上腺，

33、它分泌可的松和腎上腺激素。胰腺不僅分泌消化酶，而且分泌胰島素和高血糖素，這兩種激素控制機(jī)體的糖分及淀粉的消耗。 The nervous system. The brain, the spinal cord and the nerve - also controls body activities. The lower parts of the brain control basic functions such as breathing and heart rate as well as body temperature, hunger, and thirst. Above these reg

34、ions are the centers for sight, sound, touch, smell, and taste, and the regions that direct voluntary muscular activities of the arms and legs. Performed here are the higher functions of integrating and processing information. 神經(jīng)系統(tǒng)腦、脊髓及神經(jīng)，也調(diào)控機(jī)體活動(dòng)。腦的偏下部位控制著諸如呼吸、心跳、體溫、饑渴的基本活動(dòng)。而腦的偏上部位則是視覺(jué)、聽(tīng)覺(jué)、觸覺(jué)、嗅覺(jué)及味覺(jué)中心

35、，也是指揮臂、腿隨意肌肉運(yùn)動(dòng)的區(qū)域。神經(jīng)系統(tǒng)更高級(jí)的功能是整合、處理信息。 The brain receives and sends information by means of nerves, many of which lie partly in the spinal cord. The spinal cord is protected by the spinal column. Nerves enter and leave the spinal cord at each level of the body, traveling to and from the arms, legs, a

36、nd trunk. These nerves bring information from the various sense organs. The information is processed by the brain, and then messages are carried back to muscles and glands through out the body. 腦通過(guò)神經(jīng)收集并傳送信息，許多神經(jīng)部分地分布在脊髓里。脊髓由脊柱保護(hù)。在機(jī)體每一級(jí)，神經(jīng)傳人、傳出脊髓，往返于臂、腿、軀體。這些神經(jīng)輸送來(lái)自各種感覺(jué)器官的信息。信息經(jīng)腦處理后輸送回全身及腺體 The reprod

37、uctive system is constructed differently for males and females. The male reproductive system is responsible for producing, transporting and maintaining viable sperm (the male sex cell). It also produces the male sex hormone, testosterone, which regulates the development of a beard, pubic hair, a dee

38、p voice and other bodily characteristics of the adult male. 男、女性的生殖系統(tǒng)不同。男性生殖系統(tǒng)產(chǎn)生、輸送、維持能存活的精子（男性性細(xì)胞）。它也分泌男性激素、睪酮，以此調(diào)節(jié)胡須、陰毛、深沉嗓音極其他成年男子身體發(fā)育的特征。 The female productive system is responsible for producing and transporting ova (the female sex cells), eliminating ova from the body when they are not fertili

39、zed by sperm, nourishing and providing a place for growth of an embryo when an ovum is fertilized by sperm, and nourishing a newborn child. The female reproductive system also produces the female sex hormones, estrogen and progesterone, which regulate the development of breasts and other bodily char

40、acteristics of the mature female. 女性生殖系統(tǒng)產(chǎn)生、輸送卵子（女性性細(xì)胞），將未受精的卵子排出體外，而當(dāng)精、卵結(jié)合時(shí)，女性生殖系統(tǒng)培養(yǎng)、提供胚胎生長(zhǎng)場(chǎng)所，并孕育新生兒。女性生殖系統(tǒng)也分泌女性性激素雌激素和孕酮，以此調(diào)節(jié)乳房及其他成熟女性身體發(fā)育的特征。 The skin is a complete layer that protects the inner structures of the body, and it is the largest of the bodys organs. It keeps out foreign substances and

41、prevents excessive water evaporation. The nerves in the skin provide tactile information. The skin also helps keep the bodys temperature close to 37 C, heat is conserved by reducing blood flow through the skin or is expended by increasing blood flow and by evaporation of sweat from the skin. Hair an

42、d nails are accessory structures of the skin. 皮膚是保護(hù)肌體內(nèi)層結(jié)構(gòu)的完整層，也是機(jī)體的最大器官。皮膚防御外來(lái)侵襲，防止過(guò)多水分蒸發(fā)。皮膚上的神經(jīng)提供觸覺(jué)信息。皮膚也能將體溫維持到98.6華氏度（約37攝氏度）。通過(guò)皮膚的血流量降低時(shí)，熱量就被儲(chǔ)存起來(lái)，通過(guò)皮膚的血流增加及汗液蒸發(fā)時(shí)，熱量就散發(fā)。頭發(fā)及指甲是皮膚的附屬結(jié)構(gòu)。 Cells and Tissues細(xì)胞與組織In this passage, you will learn:1.Human body systems as a whole 2.Vital parts of a cell 3.F

43、our kinds of tissuesCells are organized into tissues, and tissues are arranged into organs, which in turn are grouped into systems. Each body system serves its specific functions. Bear in mind however that the body functions as a wholeno system is independent of the others. They work together to mai

44、ntain the bodys state of internal stability, termed homeostasis. Now lets begin our discussion with cells, the smallest unit of living matter that can exist by itself. 細(xì)胞構(gòu)成組織，組織構(gòu)成器官，器官又進(jìn)一步構(gòu)成系統(tǒng)。人體的每個(gè)系統(tǒng)都有其特定功能，但是，請(qǐng)記住這里:機(jī)體是作為一個(gè)整體來(lái)發(fā)揮作用的，沒(méi)有哪個(gè)系統(tǒng)能夠獨(dú)立于其他系統(tǒng)而存在，是整體系統(tǒng)共同作用保持了機(jī)體內(nèi)部的穩(wěn)定狀態(tài)，即體內(nèi)平衡?，F(xiàn)在，我們先討論細(xì)胞能獨(dú)立存在活性物質(zhì)的

45、最小單位。 The body can be studied from its simplest to its most complex level, beginning with the cell. All body functions result from the activities of billions of the specialized cells. Some plants and animals consist of only a single cell. Others are composed of many billions of cells. 從細(xì)胞開(kāi)始，我們能夠從最簡(jiǎn)單

46、到最復(fù)雜的水平來(lái)研究機(jī)體。所有人體的功能都來(lái)自億萬(wàn)個(gè)特定細(xì)胞活動(dòng)，有的動(dòng)植物僅由一個(gè)細(xì)胞構(gòu)成，其他生物則由億萬(wàn)個(gè)細(xì)胞構(gòu)成。Cells exist in a variety of shapes and sizes. They may, for example, be cube-shaped or flat. Scientists who study cells have determined that a single cell may be as large as a tennis ball or so small that thousands would fit on the point o

47、f a needle. The yolk of a hens egg is actually a very large cell. By contrast, bacteriaeach one of which is a tiny cellare among the smallest cells. Regardless of its shape or size, every cell contains the “machinery” needed to maintain life. While normally cells function with great efficiency, they

48、 are subject to various disorders that result in disease. 細(xì)胞有很多種形狀和大小。列如：有可能是立方形或扁形的。科學(xué)家的研究發(fā)現(xiàn)單獨(dú)一個(gè)細(xì)胞可以像網(wǎng)球一樣的大小，或小到幾千個(gè)細(xì)胞才能剛好填滿針頭。雞的蛋黃是一個(gè)非常大的單細(xì)胞。微小的細(xì)菌呢算是最小的細(xì)胞。不管是細(xì)胞大小或形狀的不同，每個(gè)細(xì)胞都有“需要存活的機(jī)制”。對(duì)每個(gè)正常的細(xì)胞，有效力的細(xì)胞，都存在許多問(wèn)題，能導(dǎo)致疾病。The size of cells is usually measured in microns. A micron is a millionth of a meter

49、, and about 25,000 microns equal one inch. The smallest bacteria are about 0.2 micron in diameter. The average cell in the human bodyabout ten microns in diameteris a speck barely visible without the aid of a microscope. 細(xì)胞的大小是以“微米”為長(zhǎng)度單位。微米是一米的一百萬(wàn)分之一，25000微米等于一寸。最小的細(xì)菌的圓徑是0.2微米。人體正常細(xì)胞的評(píng)價(jià)圓徑約十微米，肉眼勉強(qiáng)可以

50、看得到，不需要顯微鏡的幫助。 The study of cells is the branch of biology called cytology. The science that deals with cells on the smallest structural and functional level is called molecular biology. 研究關(guān)于“細(xì)胞”是生物學(xué)的分支，成為細(xì)胞生物學(xué)。在最微小水平針對(duì)細(xì)胞的結(jié)構(gòu)及功能的研究成為分子生物學(xué)。 All cells consist of protoplasm, the “l(fā)iving jelly.” The prot

51、oplasm of a typical cell forms three vital partsthe cell membrane, the cytoplasm, and the nucleus. The membrane encloses the other cell structures. Much of the chemical work of the cell is done in the cytoplasm, which surrounds the nucleus. The nucleus, enclosed by its own membrane, is the control c

52、enter of the cell. (see Figure 1-1) 所有細(xì)胞都是以“原生質(zhì)”，又稱“生命膠質(zhì)”所形成的。典型細(xì)胞的原生質(zhì)形成了三個(gè)重要部分，細(xì)胞膜、細(xì)胞質(zhì)和細(xì)胞核。細(xì)胞膜圈住了細(xì)胞的其他結(jié)構(gòu)。大部分的化學(xué)反應(yīng)都在細(xì)胞核周圍，細(xì)胞質(zhì)完成的。被自己的膜包圍的細(xì)胞核是細(xì)胞的控制中心。the cells Membrane細(xì)胞膜 Cells can survive only in a liquid medium that brings in food and carries away waste. For one-celled organisms this fluid is an e

53、xternal body of waterthe ocean, a lake, or a stream. For many-celled plants and animals, however, the medium is part of the organismin plants, the sap; in animals, the blood. 細(xì)胞只能存活在能供養(yǎng)分又能排除廢物的液體媒介中。對(duì)單細(xì)胞生物來(lái)說(shuō)，這就是細(xì)胞外的液體，如：大海里、河里或水流中。在對(duì)多細(xì)胞生物而言，這種媒介就是生物體的一部分，植物以汁液的形式，動(dòng)物以血液的形式。 The cell membrane is semip

54、ermeable, or differentially permeablesome substances can pass through it, but others cannot. This characteristic enables the cell to admit useful substances and to reject harmful substances from the surrounding fluid as well as to force out, or excrete waste products into the fluid. 細(xì)胞膜是半滲透性或區(qū)別性的滲透膜

55、，即某些物質(zhì)能滲透。這個(gè)特殊性使細(xì)胞對(duì)細(xì)胞周圍只吸收了需要的物質(zhì)而排除掉有害的物質(zhì)，包括細(xì)胞內(nèi)的廢物通過(guò)液體化后排出細(xì)胞外。 The cell membrane is an extremely thin but tough band of protein and phospholipid molecules. Phospholipids are chemicals similar to stored fat. On the evidence of electron micrographs, biologists believe that it has pores through which c

56、ertain small molecules pass intact. Substances probably pass through the cell membrane in several ways. Small chambers located on the cell membrane called caveolae gather chemical signals and channel them into the cells. The caveolae may also help distribute proteins throughout the cell. Large molec

57、ules enter the cell by a process called diffusion, in which they may be dissolved by substances in the cell membrane. They can then through the membrane without difficulty. Some cells take in large molecules by means of pinocytosis. In this process, the cell membrane forms a pocket around large mole

58、cules floating against it. The molecule-and-fluid-filled pocket then breads loose from the membrane to become a bubblelike vacuole, and the vacuole then drifts into the cytoplasm. Finally, the vacuole wall breaks up and the molecules are released into the cytoplasm. 細(xì)胞膜是一種非常薄但確以很堅(jiān)固的蛋白磷脂膜形成。磷脂是一種類似于儲(chǔ)

59、存的脂肪的蛋白物質(zhì)。通過(guò)電子顯微鏡，生物學(xué)家相信細(xì)胞膜有孔，使較小的物質(zhì)完全可以通過(guò)。物質(zhì)可通過(guò)多種方式從細(xì)胞膜進(jìn)入。細(xì)胞膜上的結(jié)構(gòu)，稱“小穴”，可接受化學(xué)信號(hào)再傳到細(xì)胞內(nèi)。小穴還可能參于細(xì)胞蛋白的分配。大的分子可通過(guò)“滲濾”進(jìn)入細(xì)胞內(nèi)，或被細(xì)胞膜內(nèi)體分解，使它們更容易的進(jìn)入細(xì)胞內(nèi)。有些細(xì)胞可通過(guò)“胞飲”方式吞飲較大的物質(zhì)。這個(gè)過(guò)程是通過(guò)細(xì)胞膜在大物質(zhì)形成了“帶”把它包圍著，將它以泡狀的“液泡”引入細(xì)胞質(zhì)，最后包圍解散，大物質(zhì)成功的進(jìn)入細(xì)胞內(nèi)。The cytoplasm細(xì)胞質(zhì) The cytoplasm is mainly water. Its water content varies fro

60、m a minimum of about 65 percent to a maximum of about 95 percent. The solids in the cytoplasm include granular proteins, carbohydrates, droplets of fat, and pigments. The cytoplasm is thus a colloidal system. 細(xì)胞質(zhì)主要成分是“水”。水分含量有百分之65到最高，百分之95。細(xì)胞質(zhì)內(nèi)的固體包括蛋白顆粒、碳水化合物、脂肪小滴和色素。細(xì)胞質(zhì)是膠體性的。 The cytoplasm may be