医学专业英语 Chapter 5 Respiratory System.pdf

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1、Chapter 5Chapter 5Respiratory SystemRespiratory SystemIn this passage you will learn:The organs of the respiratory system The structure and function of these organs The mechanism of breathing The gas transport and cleaning system All living animals must take in oxygen and get rid of carbon dioxide.I

2、n thevertebrates animals with backbones that get their oxygen from the air,bothtasks are performed by special gas-exchange organs called lungs.The lungs providea place where oxygen can reach the blood and carbon dioxide can be removed from it.They are equipped with tubes and a bellows system for dra

3、wing in air from the outside,while the pulmonary veins and arteries circulate blood through from inside.The lungsalso have a cleaning system that traps,ejects,or destroys irritants and otherharmful substances that travel in with the air.In the simpler cold-blooded amphibians and reptiles,the lungs a

4、re twoballoon-like sacs.In active animals that require large amounts of oxygen,especially the warm-blooded birds and mammals,the lungs are a spongy labyrinthof sacs that supply an enormous surface area for the transfer of gases.In the adulthuman the total lung surface,if flattened out,would be large

5、r than a badmintoncourt,about 100 square yards(83 square meters).Air enters the body through the nose and passes through the nasal cavity,whichis lined with a mucous membrane and fine hairs(cilia)to help filter out foreignbodies,as well as to warm andmoisten the air.Paranasal sinuses are hollow,air-

6、containing spaces within the11skull that communicate with the nasal cavity.They,too,have a mucous membranelining and function to provide the lubricating fluid mucus.as well as to lightenthe bones of the skull and help produce sound.After passing through the nasal cavity,the air next reaches the phar

7、ynx(throat).There arethree divisions of the pharynx.The nasopharynx is the first division,and it isnearest to the nasalcavities.It contains the adenoids,which are masses of lymphatic tissue.Theadenoids(also known as the pharyngeal tonsils)are more prominent in children,andif enlarged,they can obstru

8、ct air passageways.Below the nasopharynx and closerto the mouth is the second division of the pharynx,the oropharynx.The palatinetonsils,two rounded massed of lymphatic tissue,are located in the oropharynx.Thethird division of the pharynx is the hypopharynx(also called the laryngopharynx).It is in t

9、he hypopharyngeal region that the pharynx,serving as a commonpassageway for food from the mouth and air from the nose,divides into two branches,the larynx(voice box)and the esophagus.The esophagus leads into the stomach and carries food to be digested.The larynxcontains the vocal cords and is surrou

10、nded by pieces of cartilage for support.Soundsare produced as air is expelled past the vocal cords,and the cords vibrate.Thetension of the vocal cords determines the high or low pitch of the voice.Since food entering from the mouth and air entering from the nose mix in thepharynx,what prevents the p

11、assing of food or drink into the larynx and respiratorysystem after it has been swallowed Even with a small quantity of solid or liquidmatter finding its way into the air passages,breathing could be seriously blocked.A special deterrent to this event is provided for by a flap of cartilage attachedto

12、 the root of the tongue that acts like a lid over the larynx.This flap of cartilageis called the epiglottis.The epiglottis lies over the entrance to the larynx.In22v1.0 可编辑可修改the act of swallowing,when food and liquid move through the throat,the epiglottiscloses off the larynx,so that these things c

13、annot enter.On its way to the lungs,air passes from the larynx to the trachea(windpipe),a vertical tubeabout 412 inches long and 1 inch in diameter.The trachea is kept open by 16-20C-shaped rings of cartilage separated by fibrous connective tissue that stiffensthe front and sides of the tube.In the

14、region of the mediastinum,the trachea dividesinto two branches called bronchi.Each bronchus leads to a separate lung and dividesand subdivides into smaller and finer tubes,somewhat like the branches of a tree(see Figure 6-1).DiaphragmFigure 6-1Figure 6-1 The smallest of the bronchial branches are ca

15、lled bronchioles.At the end ofthe bronchioles are clusters of air sacs called alveoli.Each alveolus is made ofa one-cell layer of epithelium.The very thin wall allows for the exchange of gasesbetween the alveolus and the capillaries that surround and come in close contactwith it.The blood that flows

16、 through the capillaries accepts the oxygen from thealveolus and deposits carbon dioxide into the alveolus to be exhaled.Oxygen iscombined with a hemoglobin in erythrocytes and carried to all parts of the body.Each lung is enveloped in a double-folded membrane called the pleura.The outer33layer of t

17、he pleura,nearest the ribs,is the parietal pleura,and the inner layer,closest to the lung,is the visceral pleura.The pleura is moistened with a seroussecretion that facilitates the movements of the lungs within the thorax.The two lungs are not quite mirror images of each other.The right lung,whichis

18、 the slightly larger of the two,is divided into three lobes,or divisions,andthe left lung is divided into two lobes.It is possible for one lobe of the lungto be removed withoutdamage to the rest,which can continue to function normally;The uppermost part of the lung is called the apex,and the lower a

19、rea is the base.The hilum of the lung is the midline region where blood vessels,nerves,and bronchialtubes enter and exit the organ.The lungs extend from the collarbone to the diaphragm in the thoracic cavity.The diaphragm is a muscular partition that separates the thoracic from the abdominalcavity a

20、nd aids in the process of breathing.The diaphragm contracts and descendswith each inhalation(inspiration).The downward movement of the diaphragm enlargesthe area in the thoracic cavity and reduces the internal air pressure,so that airflows into the lungs to equalize the pressure.When the lungs are f

21、ull,the diaphragmrelaxes and elevates,making the area in the thoracic cavity smaller,and thusincreasing the air pressure in the thorax.Air then is expelled out of the lungsto equalize the pressure;this is called exhalation(expiration).Other parts arealso involved in the process.The cycle of respirat

22、ion really begins when the phrenicnerve stimulates the diaphragm to contract and flatten.Also,the intercostalmuscles between the ribs aid in inspiration by pulling the ribs up and out.Themeasure of how easily the lungs expand under pressure is compliance.Breathing is regulated unconsciously by cente

23、r in the brainstem.These centersadjust the rate and rhythm of breathing according to changes in the composition ofthe blood,especially the concentration of carbon dioxide.Gas Transport.Oxygen is carried in the blood bound to hemoglobin in red blood44cells.The oxygen is released to the cells as neede

24、d.Carbon dioxide is carried inseveral ways,but is mostly converted to an acid called carbonic acid.The amountof carbon dioxide that is exhaled is important in regulating the acidity oralkalinity of the blood.If too much carbon dioxide is exhaled by hyperventilation,body fluids tend to become more al

25、kaline,a condition termed alkalosis.If too littlecarbon dioxide is exhaled as a result of hypoventilation,body fluids tend to becomemore acid,a condition termed acidosis.The cleaning systemThe cleaning system of the lungs has four main components.Lining the tracheaand bronchial tree are cells that s

26、ecrete mucus,which traps pollutants and bacteria.Also in the bronchi arecells containing tiny cilia,that project into the blanketof mucus and with constant wavelike motions push the mucus up out of the airways.Irritating chemicals,stagnant and excessive mucus,and large bits of foreign matterare forc

27、ibly ejected as sputum from the bronchi by a cough.This third importantcleaning device like breathing,under partial voluntary control is a rapidmuscle contraction and bronchial-tube constriction that generates a wind force farstronger than a tornado.Small harmful substances that make their way into

28、thealveoli are destroyed by the fourth line of defense,the macrophages.These arepatrolling cells that swallow up foreign particles or destroy them with enzymes.New Words and PhrasesNew Words and Phrases55v1.0 可编辑可修改66v1.0 可编辑可修改ExercisesExercises77A.Discuss the following topics:A.Discuss the followi

29、ng topics:1.Imagine you were lecturing in front of rural health workers on the topic ofrespiratory system,draw a picture to illustrate the whole system.2.Describe their structures and functions.3.How can epiglottis prevent the passing food and drink into the respiratory system4.What role does the di

30、aphragm play in the process of breathing5.What are the four components of the cleaning system How do they functionB.B.FillFill inin thethe blanksblanks withwith thethe wordswords givengiven belowbelow andand changechange theirtheir formsforms ifif necessary.necessary.alveoluscapillarydiaphragmhemogl

31、obinthoraciccavitygas exchangeparietalpleuravisceralpleura The lungs are two cone-shaped,spongy organs consisting of alveoli,bloodvessels,elastic tissue and nerves.Each of the two lungs consists of smallerdivisions called lobes;the left lung hastwo lobes,while the right lung is dividedinto three lob

32、es.In the lungs,(1)are surrounded by a network of tiny blood vesselscalled capillaries;oxygen from thelungs passes into these(2)for distributionto tissue cells,while carbon dioxide from the blood passes into the lungs to beexpelled by exhalation.Once absorbed into blood cells,oxygen becomes attached

33、 to(3)and is released to tissue cells as needed.Thus,the primary function of thelungs is to bring air into close contact with blood,which allows(4)to occur.The lungs are surrounded by a membrane called the(5).The space that thelungs occupy within the chest is called the(6),which is lined by a membra

34、necalled the(7).The parietal and visceral pleurae lie very close to each other;88mediastinumpleural spacethe small space between theses membranes,called the(8),is filled with a fluidthat prevents friction when the two membranes slide against each other duringrespiration.In the central portion of the

35、 thoracic cavity(in the area between thelungs)is a space called the(9),which contains the heart.A group of smoothmuscles called the (10)separates the lower portion of the thoracic cavity fromthe abdomen.C.Match Column I with Column n.C.Match Column I with Column n.Column IColumn Ibronchiolecomplianc

36、e 1 2 Column IIColumn IIany of the small subdivision of the bronchithe peak portion of the lungsa condition in which there is too much carbon dioxidehypoventilation 3 in the bloodintercostalparanasal sinuses 4 5 between the ribsair-conditioning cavities in the bones near the nosea condition in which

37、 there is too much carbon dioxideacidosis 6 in the bloodapex 7 weak,inadequate exchange of gasrounded masses of lymph tissue in the oropharynxpharynx 8(palatinemeans roof of the mouth).alkalosis 9 in agreement withthroat;composed of the nasopharynx,oropharynx,andpalatine tonsils 10 laryngopharynx.D.

38、Define the following terms of the respiratory system in line with the text youD.Define the following terms of the respiratory system in line with the text youhave just,learned(making use of the vocabulary provided in the brackets ifhave just,learned(making use of the vocabulary provided in the brack

39、ets ifnecessary),for exam-ple:necessary),for exam-ple:99the gas needed by cells to releaseenergy from food in metabolismOxygenOxygen(gas,cell,release energy fromfood,metabolism)1.mirror imagemirror image(as seen,right side,as if,left side,vice versa)2.adenoidsadenoids(lymphatic tissue,nasophar-ynx)3

40、.alveolusalveolus(air sac,gas exchange,inrespiration)4.bronchusbronchus(main branch,trachea,mediastinum)5.epiglottisepiglottis(leaf-shaped,cartilage,larynx,prevent,trachea)6.hyperventilationhyperventilation(extreme,rapid,deep,result in,alkalosis)7.diaphragmdiaphragm(dome-shaped,muscle,move,increase,

41、decrease,space,thoracic cavity)8.pharynx(common,passageway,esophagus,food,air,larynx)9.pleura(double-layered,membrane,visceral pleura,pariatal pleura,tho-racic cavity)10.sputum (substance,releases,coughing,clearing the throat,res-piratory tract)1010E.Translate the following into English.E.Translate

42、the following into English.1.副鼻窦3.脊椎动物5.二氧化碳7.横膈膜神经9.威慑物11.滞痰13.纵隔15.碱中毒17.污染物质2.口咽4.肺泡6.肺换气不足8.双重折叠的10.润滑液12.食管14.哺乳动物16.迷宫18.脑干20.刺激物19.上皮；上皮细胞Passage Two Respiratory Disorders and DiseasesPassage Two Respiratory Disorders and DiseasesIn this passage you will learn:Various disorders and diseases o

43、f the respiratory system Their definitions,causes and treatmentDetailed description of the signs and symptoms of chronic obstructivepulmonary disease Medical terms pertaining to the diseases of the respiratory system The respiratorysystem is subject to a wide variety of disorders and diseases.The mo

44、st frequent attacks come from common cold and flu viruses.Other diseases thataffect the lungs includebacterialinfectionssuch as pneumoniaand tuberculosis.Thelungs are especiallyvulnerableto allergicdis-eases such as asthma.There are moreserious diseases such as respiratory distress syndrome,em-physe

45、ma,chronic obstructive pulmonary diseases(COPD),lung cancer,etc.InfluenzaInfluenza andand pneumonia.pneumonia.Influenza is a viral disease of the respiratory tract.Different strainsof theinfluenzavirushavecausedseriousepidemicsthroughhistory.1111Pneumonia is caused by several different microorganism

46、s.The name represents anyinflammation of the lungs caused by in-fection,so an alternate term for pneumonia is pneumonitis.Streptococcal pneumoniausually in-volves one or more lobes of the lung and described as lobar pneumonia.Other agents of pneumonia localize in the bronchial tubes,causing bronchop

47、neumonia.PleurisyPleurisy is severe chest pain accompanying each deep breath in a person withan inflamed pleura,the twin membranes around each lung and lining the chest cavity.Pleurisy can attend pneu-monia or result from direct infection of the pleura.TuberculosisTuberculosis(TB(TB)has increased in

48、 recent years along with the rise of AIDS andthe appear-ance of resistance to antibiotics in the organism that causes the disease.The nameof the disease comes from the small lesions,or tubercles,that appear with theinfection.The symptoms of TB in-clude fever,weight loss,weakness,cough,and as a resul

49、t of damage to blood vesselsin the lungs,hemoptysis,i.e.the coughing up of phlegm(sputum)containing blood.Accumulation of exudatein the alveoli may result in solidification or consolidation of lung tissue.Thetuberculin test is used to reveal tuberculosis infection,PPD(purified proteinderivative)is t

50、he form of tuberculin commonly used.Asthma Asthma.Attacks of asthma result from narrowing of the bronchial tubes.Theconstriction,a-long with edema,swelling of the bronchiallinings,and accumulationof mucus resultsin wheezing,extreme dyspnea and cyanosis.Although the cause of asthma is uncertain,forei