1、文檔編碼 : CG5C5Y2W3J3 HI7A4N2L4J5 ZD2E8P8H10V8Introduction to Physiology 生理學簡介Introduction 介紹Physiology is the study of the functions of living matter. It is concerned with how an organism performs its varied activities: how it 生理學是爭論生物體功能的科學；它 爭論生物體如何進行各種活動,如何飲食,feeds, how it moves, how it adapts to c

2、hanging circumstances, how it 如何運動, 如何適應不斷轉變的環境,如何spawns new generations. The subject is vast and embraces the whole of 繁殖后代； 這門學科包羅萬象,涵蓋了生物life. The success of physiology in explaining how organisms perform their daily tasks is based on the notion that they are intricate and exquisite machines whos

3、e operation is governed by the laws of physics and 體整個生命過程；生理學成功地說明白生 物體如何進行日?；顒?基于的觀點是生 物體好比是結構復雜而敏捷的機器,其操chemistry. 作受物理和化學規律把握；Although some processes are similar across the whole spectrum of 盡管從生物學整個范疇看,生物體某biology the replication of the genetic code for or example些活動過程是相像的 如基因編碼的復specific to pa

4、rticular groups of organisms. For this reason it is necessary to divide the subject into various parts such as bacterial physiology, plant physiology, and animal physiology.制 但許多過程仍是某些生物體群組特 有的；鑒于此有必要將這門學科分成不同部分爭論, 如細菌生理學、 植物生理學和動To study how an animal works it is first necessary to know how it is 物

5、生理學；built. A full appreciation of the physiology of an organism must therefore be based on a sound knowledge of its anatomy. Experiments can then be carried out to establish how particular parts perform their functions. Although there have been many important physiological investigations on human vo

6、lunteers, the need for precise control over the experimental conditions has meant that much of our present physiological knowledge has been derived from studies on other animals such as frogs, rabbits, cats, 要爭論一種動物如何活動,第一需要 明白它的構成；要充分明白一個生物體的 生理學活動就必需把握全面的解剖學知 識；一個生物體的各部分起著什么作用可 通過試驗觀看得知；盡管我們對理想者進

7、行了許多重要的生理調查,但是試驗條件 需要精確把握,所以我們當前大多生理知and dogs. When it is clear that a specific physiological process has a 識仍是源于對其它動物如青蛙,兔子,貓和common basis in a wide variety of animal species, it is reasonable to assume that the same principles will apply to humans. The knowledge gained from this approach has given

8、 us a great insight into human 狗等的爭論；當我們明確大多數動物物種 的特定生理過程存在共同之處時,相同的 生理原理適用于人類也是合理的；通過這physiology and endowed us with a solid foundation for the effective 種方法, 我們獲得了大量的學問,從而讓我treatment of many diseases.The building blocks of the body are the cells, which are grouped 們對人類生理學有了更深化的明白,為我 們有效治療許多疾病供應了一個

9、堅實的基together to form tissues. The principal types of tissue are epithelial, 礎；connective, nervous, and muscular, each with its own characteristics. Many connective tissues have relatively few cells but have an extensive 機體的基本組成物質是細胞,細胞結 合在一起形成組織；組織的基本類型有上extracellular matrix. In contrast, smooth mus

10、cle consists of densely 皮組織, 結締組織, 神經組織和肌組織,每packed layers of muscle cells linked together via specific cell junctions. Organs such as the brain, the heart, the lungs, the intestines, and the liver are formed by the aggregation of different kinds of tissues. The organs are themselves parts of distin

11、ct physiological systems. The heart and blood vessels form the cardiovascular system; the lungs, trachea, and bronchi together with the chest wall and diaphragm form the respiratory system; the skeleton and skeletal muscles form the musculoskeletal system; the brain, spinal cord, autonomic nerves an

12、d ganglia, and peripheral somatic nerves form the nervous system, and so on.Cells differ widely in form and function but they all have certain common characteristics. Firstly, they are bounded by a limiting membrane, the plasma membrane. Secondly, they have the ability to break 類組織都有各自的特點；許多結締組織中 細胞

13、量相對較少,但是有大量的細胞外基 質；相比而言, 光滑的肌組織由大量密密麻 麻的肌細胞通過特定的細胞連接組成；各 種器官如腦, 心臟,肺,小腸和肝等由不同 種類的組織集合而成；這些器官是不同生 理系統的組成部分；心臟和血管組成心血 管系統； 肺,器官, 支氣管, 胸壁和膈肌組 成呼吸系統；骨骼和骨骼肌組成骨骼肌系 統；大腦,脊髓,自主神經和神經中樞以及 四周軀體神經組成神經系統等等；細胞在形體和功能上差異很大,但是down large molecules to smaller ones to liberate energy for their activities. 它們有某些共同的特點；第一

14、,它們由限制Thirdly, at some point in their life history, they possess a nucleus which contains genetic information in the form of deoxyribonucleic acid DNA.膜包被, 即細胞質膜； 其次,細胞有把大分 子分解為小分子來釋放活動所需能量的能Living cells continually transform materials. They break down 力；第三,在生命過程中某個階段,細胞體glucose and fats to provide

15、energy for other activities such as motility and 內存在一個以脫氧核糖核酸 DNA 形式包the synthesis of proteins for growth and repair. These chemical changes are collectively called metabolism. The breakdown of large molecules to smaller ones is called catabolism and the synthesis of large molecules from smaller one

16、s anabolism. In the course of evolution, cells began to differentiate to serve different functions. Some developed the ability to contract muscle cells, others to conduct electrical signals nerve cells. A further group developed the ability to secrete different substances such as hormones or 含基因信息的細

17、胞核；活體細胞不斷轉化物質；它們為其它 活動供應能量分解葡萄糖和脂肪,比如自 身生長和修復所需的蛋白質運動和合成；這些化學變化統稱為新陳代謝；把大分子 分解為小分子的過程稱為分解代謝,小分 子合成大分子的過程稱為合成代謝；細胞在進化過程中不斷分化進行不同enzymes. During embryological development, this process of 的功能活動； 有些細胞具有收縮才能（如肌differentiation is re-enacted as many different types of cell are formed from the fertilized e

18、gg. Most tissues contain a mixture of cell types. For example, blood consists of red cells, white cells, and platelets. Red cells transport oxygen around the body. The white cells play an important role in defense against infection and the platelets are vital components in the process of blood clott

19、ing. There are a number of different types of connective tissue but all are characterized by having cells distributed within an extensive noncellular matrix. Nerve tissue contains nerve cells and glial cells.The Principal Organ SystemsThe cardiovascular system 細胞）,有些可以傳導電信號（如神經細 胞）；進一步進化的細胞能夠分泌不同物質

20、如荷爾蒙 （如內分泌細胞） 或酶；胚胎發育 過程中,分化的過程由于許多不同細胞來 源于受精卵而再次發生；大多數組織包含有不同的細胞類型；比如,血液中含紅細胞,白細胞和血小板；紅細胞運輸全身的氧氣；白細胞在抵抗感 染時起重要作用,血小板是血液凝集過程 中重要的成分；結締組織有多種不同類型,但有一個共同特點,即細胞分布在豐富的 細胞外基質中；神經組織含神經細胞和神The cells of large multicellular animals cannot derive the oxygen and 經膠質細胞；nutrients they need directly from the exter

21、nal environment. The oxygen 主要的器官系統and nutrients must be transported to the cells. This is one of the principal functions of the blood, which circulates within blood vessels by virtue of 心血管系統the pumping action of the heart. The heart, blood vessels, and associated tissues form the cardiovascular sy

22、stem.The heart consists of four chambers, two atria and two ventricles, which form a pair of pumps arranged side by side. The right ventricle 大型多細胞動物體的細胞不能從外界 環境中獵取直接所需的氧氣和養分物質；這些氧氣和養分物質必需轉運到細胞；這 是血液的主要功能之一,血液憑借心臟的pumps deoxygenated blood to the lungs where it absorbs oxygen from the 泵血作用在血管內流淌循環；心臟

23、、血管和air, while the left ventricle pumps oxygenated blood returning from the lungs to the rest of body to supply the tissues. Physiologists are concerned with establishing the factors responsible for the heartbeat, how the heart pumps the blood around the circulation, and how it is distributed to per

24、fuse the tissues according to their needs. Fluid exchanged between the blood plasma and the tissues passes into the lymphatic system, which eventually drains back into the blood.The respiratory system The energy required for performing the various activities of the body 結締組織組成了心血管系統；心臟包括四個腔,兩個心房和兩個心

25、 室構成了一對并排存在的泵；右心室將脫 氧的血液泵至肺中,肺中的血液吸取空氣 中的氧氣,而左心室把從肺回流來的有氧 血液泵出至身體其它部位,供應給各組織；生理學家爭論促使心臟跳動的因素,心臟 如何泵送血液使其循環,心臟如何依據各 組織所需支配血液；血漿和組織間的流淌 液體交換流入淋巴系統,最終回流到血液is ultimately derived from respiration. This process involves the oxidation of foodstuffs to release the energy they contain. The oxygen needed for

26、this process is absorbed from the air in the lungs and carried to the tissues 中；呼吸系統by the blood. The carbon dioxide produced by the respiratory activity of 機體進行各項活動所需的能量最終來the tissues is carried to the lungs by the blood in the pulmonary artery 源于呼吸； 這一過程包括食物 （主要是糖類where it is excreted in the expir

27、ed air. The basic questions to be answered 和脂肪） 的氧化, 釋放它們所含的能量；這include the following: How is the air moved in and out of the lungs. How 一過程中, 氧氣來自于肺中的空氣,經由血is the volume of air breathed adjusted to meet the requirements of the body. What limits the rate of oxygen uptake in the lungs.The digestive s

28、ystem The nutrients needed by the body are derived from the diet. Food is 液到達全身各組織；組織呼吸活動中釋放 的二氧化碳由肺動脈中的血液運輸至肺,然后呼氣排出體外；需回答的基本問題如 下：空氣是如何進出肺的？呼吸的空氣量 如何適應機體所需？限制肺吸取氧氣頻率taken in by the mouth and broken down into its component parts by enzymes in the gastrointestinal tract. The digestive products are t

29、hen absorbed into the blood across the wall of the intestine and pass to the liver 的因素是什么？消化系統via the portal vein. The liver makes nutrients available to the tissues both for their growth and repair and for the production of energy. In the case of the digestive system, key physiological questions ar

30、e: How is food 機體所需養分物質來源于飲食；食物 經口腔進入體內,在胃腸道內經酶將其分 解成小分子物質；這些消化物通過腸壁吸ingested. How is it broken down and digested. How are the individual 收入血液, 通過門靜脈進入肝臟；經肝臟作nutrients absorbed. How is the food moved through the gut. How are the indigestible remains eliminated from the body.The kidneys and urinary t

31、ract The chief function of the kidneys is to control the composition of the extracellular fluid. In the course of this process, they also eliminate non-用后,這些養分物質能夠中意組織生長修 復及能量需求； 在消化系統部分, 重要的生 理學問題是：食物是如何消化的？食物如 何被個體分解消化？個體養分物質如何吸 收？食物如何在腸內轉運的？未消化的殘 留如何從體內排出？volatile waste products from the blood. T

32、o perform these functions, the kidneys produce urine of variable composition which is temporarily stored 泌尿系統in the bladder before voiding. The key physiological questions in this case are: how do the kidneys regulate the composition of the blood. How do they eliminate toxic waste. How do they respo

33、nd to stresses such as dehydration. What mechanisms allow the storage and elimination of the 腎臟主要功能是把握細胞外液體的形 成；在這一過程中, 腎臟也會把不行揮發的 廢物排出去；為行使這一功能,在排出之 前,腎臟產生含有各種成分的尿液并將其urine. 暫時儲存在膀胱中；這一部分主要的生理The reproductive system Reproduction is one of the fundamental characteristics of living organisms. The gon

34、ads produce specialized sex cells known as gametes. 學問題是：腎臟如何調劑血液中的成分？如何排出有毒廢物？如何應對像脫水這樣 的應激反應？以及尿液可以儲備和排出體 外的機制是什么？At the core of sexual reproduction is the creation and fusion of the male and female gametes, the sperm and ova eggs, with the result that the 生殖系統genetic characteristics of two separa

35、te individuals are mixed to produce 生殖是活生物體的一個基本特點；生offspring that differ genetically from their parents.殖腺產生特地的性細胞,被稱為配子； 性生The musculoskeletal system This consists of the bones of the skeleton, skeletal muscles, joints, 殖的核心是雌雄配子即精子和卵子的產生 和融合,因此兩個獨立個體的基因特點融 合而產生一個基因上與雙親不同的后代；and their associated t

36、issues. Its primary function is to provide a means of movement, which is required for locomotion, for the maintenance of 運動系統posture, and for breathing. It also provides physical support for the internal organs. Here the mechanism of muscle contraction is a central issue. The 這一系統由骨、 骨骼肌、關節和它們的 相關組織

37、組成；其主要功能是供應運動需endocrine and nervous systems.要,保護姿勢及呼吸運動；它也為內臟器官The endocrine and nervous systems The activities of the different organ systems need to be coordinated and regulated so that they act together to meet the needs of the body. Two coordinating systems have evolved: the nervous system and t

38、he endocrine 供應物理支持； 這一部分, 肌肉收縮機制是 主要問題；內分泌系統和神經系統不同器官系統的活動需要協作和調system. The nervous system uses electrical signals to transmit information 節,以便共同作用中意機體需要；人體有兩very rapidly to specific cells. Thus the nerves pass electrical signals to the 大調劑系統： 神經系統和內分泌系統；神經skeletal muscles to control their contract

39、ion. The endocrine system secretes chemical agents, hormones, which travel in the bloodstream to 系統通過電信號快速將信息傳導給特定細 胞；這樣神經將電信號傳遞給骨骼肌以控the cells upon which they exert a regulatory effect. Hormones play a major 制收縮；內分泌系統分泌化學物質激素；role in the regulation of many different organs and are particularly impo

40、rtant in the regulation of the menstrual cycle and other aspects of 激素通過血流到達施與調劑作用的細胞；激素在許多不同器官中起著重要作用,在reproduction. 月經期調劑和其它生殖方面特殊重要；The immune system provides the bodys defenses against infection 免疫系統通過殺死入侵的有機體,清both by killing invading organisms and by eliminating diseased or 除致病或損耗細胞為機體供應防范功能；d

41、amaged cells. 雖然爭論各器官如何行使功能很有益Although it is helpful to study how each organ performs its functions, it is essential to recognize that the activity of the body as a whole is 處,但我們必需熟識到機體作為一個整體 所做的活動依靠于各器官系統間錯綜復雜dependent on the intricate interactions between the various organ systems. 的相互作用； 假如一部分無法

42、正常工作,全If one part fails, the consequences are found in other organ systems 身其它器官系統也會受到影響；例如,假如throughout the whole body. For example, if the kidneys begin to fail, the 腎臟顯現問題, 內部環境的調劑受損,結果regulation of the internal environment is impaired which in turn leads to 導致其它器官系統功能紊亂；disorders of function els

43、ewhere. Homeostasis穩態 各種復雜機制共同作用調劑細胞外液Complex mechanisms are at work to regulate the composition of the extracellular fluid and individual cells have their own mechanisms for 的形成,不同個體細胞有自身機制調劑內 在組成成分；盡管外界環境和動物活動不regulating their internal composition. The regulatory mechanisms 停變化,調劑機制保護著體內環境的穩固；stab

44、ilize the internal environment despite variations in both the external world and the activity of the animal. The process of stabilization of the internal environment is called homeostasis and is essential if the cells of 內部環境的穩固被稱為穩態,它是機體能 夠正常發揮作用所必需的；例如,心臟的跳動依靠于心肌細胞有the body are to function normall

45、y.節律的收縮； 這一活動依靠于電信號,而電Taking one example, the beating of the heart depends on the rhythmical contractions of cardiac muscle cells. This activity depends on 信號反過來依靠存在于細胞外和細胞內液 體中鈉和鉀離子的濃度；假如細胞外液中electrical signals which, in turn, depend on the concentration of sodium 鉀離子過多, 心肌細胞興奮性增強,可能出and potassium

46、ions in the extracellular and intracellular fluids. If there is an excess of potassium in the extracellular fluid, the cardiac muscle cells 現不規律的收縮； 因此,要保護心臟正常跳 動,細胞外液中鉀離子的濃度就必需把握become too excitable and may contract at inappropriate times rather than 在確定范疇內；in a coordinated manner. Consequently, th

47、e concentration of potassium in the extracellular fluid must be kept within a narrow range if the heart is to 機體如何調劑物質成分beat normally.平穩的概念1 千克How Does The Body Regulate Its Own Composition.一天中,一個成人需要消耗約The concept of balance 食物, 23 升液體； 以一個月運算, 這相當 于約 30 千克食物, 6090 升液體；然而,In the course of a day, an

48、 adult consumes approximately 1 kg of food 一般來說, 機體體重是基本不變的；這類個and drinks 23 liters of fluid. In a month, this is equivalent to around 30 kg of food and 6090 liters of fluid. Yet, in general, body weight remains remarkably constant. Such individuals are said to be in balance; the intake of food and

49、drink matches the amounts used to generate energy for normal 體可以說處于平穩狀態；食物和液體的攝 入量相當于正常機體活動消耗的能量加上 尿液和糞便中丟失的能量；在一些情形下,如饑餓狀態,攝入量與機體所需量并不相bodily activities plus the losses in urine and feces. In some circumstances, 當,肌組織斷裂, 供應葡萄糖產生能量；蛋such as starvation, intake does not match the needs of the body and

50、 muscle tissue is broken down to provide glucose for the generation of energy. Here, the intake of protein is less than the rate of breakdown and the 白質的攝入低于肌組織斷裂的速度,機體 處于負氮平穩； 同樣地, 假如機體組織正處 于生長期, 如生長期的兒童, 孕婦和早期訓individual is said to have a negative nitrogen balance. Equally, if the body 練階段的運動員,那么蛋

51、白質的日常攝入tissues are being built up, as is the case for growing children, pregnant 量比正常機體所需要的多；相反,此時個體women and athletes in the early stages of training, the daily intake of protein is greater than the normal body turnover and the individual is in positive nitrogen balance.This concept of balance can

52、be applied to any of the body constituents including water and salt and is important in considering how the body regulates its own composition. Intake must match requirements and any excess must be excreted for balance to be maintained. Additionally, for each chemical constituent of the body there i

53、s a desirable concentration range, which the control mechanisms are adapted to maintain. For example, the concentration of glucose in the plasma is about 45mmol/L 處于 正氮 平穩；平穩的概念可以應用到機體的任何構 成成分上, 包括水和鹽, 而且平穩在機體調 節其自身成分上是特殊重要的；攝入必需 等于所需, 為保護機體平穩, 任何余外的能 量都必需排出； 此外,由于機體的每種化學 成分都有一個可取的濃度范疇,把握機制 保護這個范疇；

54、例如,兩餐間血糖濃度大約 為 45mmol/L ；進食后不久, 血糖含量超過 這一范疇,刺激胰腺分泌胰島素,降低濃between meals. Shortly after a meal, plasma glucose rises above this level 度；隨著葡萄糖濃度的下降,胰島素分泌減and this stimulates the secretion of the hormone insulin by the pancreas, which acts to bring the concentration down. As the concentration of 少；在此情形下

55、, 循環胰島素水平的轉變都 是為了使血漿中的葡萄糖保護在一個合適glucose falls, so does the secretion of insulin. In each case, the changes in 的范疇內； 這種調劑稱為負反饋機制；在胰the circulating level of insulin act to maintain the plasma glucose at an 島素分泌期間,葡萄糖像肝糖原或脂肪一appropriate level. This type of regulation is known as negative feedback. 樣被儲存

56、；During the period of insulin secretion, the glucose is being stored as either glycogen or fat.負反饋調劑是在機體顯現紊亂時,將 一些變量把握在限定范疇內的一個把握系A negative feedback loop is a control system that acts to maintain the 統；雖然上面的例子講到血糖,但這一基本level of some variable within a given range following a disturbance. Although th

57、e example given above refers to plasma glucose, the basic principle can be applied to other physiological variables such as body 原就可以應用到其它生理變量中如體溫、血壓和血漿的滲透濃度；負反饋調劑需要 一種能對不確定的變量做出反應而對其它temperature, blood pressure, and the osmolality of the plasma. A negative 生理變量不應答的傳感器；因此,滲透壓感feedback loop requires

58、a sensor of some kind that responds to the variable in question but not to other physiological variables. Thus an osmoreceptor 受器應當能對機體體液滲透的變化而不是 體溫存血壓的變化產生應答；感受器傳遞should respond to changes in osmolality of the body fluids but not to 的信息必需和理想水平（系統的調定點） 以changes in body temperature or blood pressure.

59、 the information from the 比較者的身份, 以某種方式進行比較；假如sensor must be compared in some way with the desired level by some form of comparator. if the two do not match ,an error signal is transmitted to an effector, a system that can act to restore the variable to its desired level .these features of negative

60、feedback can be appreciated by examining a simple heating system .the controlled variable is room temperature, 兩者不相符,一個錯誤信號就會傳遞給效 應器,效應器是一種能使變量保持在理想 水平的系統；負反饋的這些特點可以通過 檢測一種簡潔的加熱系統來懂得；被把握 的變量是室溫,它可以由一個溫度計檢測which is sensed by a thermostat. the effector is a heater of some kind .when 到,效應器是一種加熱器；當室溫降低到