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电大幼儿游戏与玩具形成性考核作业1-3答案资料小抄作业
一一、名词解释1.剩余精力说代表人物是席勒与斯宾塞主要观点是生物都有维持自己生存的能 力,身体健康的儿童除了维持正常生活外,还有剩余精力,剩余精力需要发泄,而游戏就是 一种剩余精力的发泄方式2.松弛说代表人物是拉察鲁斯和帕特里克主要观点是游戏不是为了剩余精力的 发泄,而是为了精力的恢复,儿童需要用游戏来恢复精力 3.前练习说又称生活预备说代表人物是格鲁斯主要观点是在童年时代就要游 戏,游戏提供了儿童准备参加严肃生活的途径,游戏是儿童未来生活最好的预备4.复演说代表人物是霍尔主要观点是游戏重演了人类进化的过程,重现了人类 进化过程中祖先的动作和活动,游戏是人类遗传活动的表现5.自主性体验谈及游戏,幼儿的心理状态总是放松的,因为他们是游戏的主人,持 有这种“权利”所引起的体验就是自主性体验6.角色扮演是一种特殊的游戏动作,是指幼儿以自身或他物为媒介对他人或他物的 动作、行为、态度进行模仿的动作,也可以说是一种象征性动作7.象征动作幼儿在游戏中的动作和生活中的基本动作不同,尽管在表现上类似,但 意义却截然不同,比如游戏中幼儿模仿日常活动中拍球的动作,不是真要玩球,而是为了符 合游戏的情景,配合游戏的需要这种动作就是象征动作,即“在表象作用支配下的想象性 虚构性动作” 8.感觉运动游戏即机能性游戏、练习性游戏、实践性游戏,是儿童最早出现的一种 形式, 一般存在于从儿童出生到 2 岁这一阶段这类游戏主要由简单的重复动作运动组成 在 运用过程中获得快感,该游戏的主要表现形式为徒手游戏或重复的操作物体的游戏9.象征性游戏是 2-7 岁学前儿童最典型的游戏形式象征即用具体的事物表现某种 特殊意义,在这一时期,幼儿的象征游戏表现为运用“替代物”,以假想的情景和行动方式 将现实生活和自己的愿望反映出来情景转变,以物代物,以人代人是象征性游戏的基本构 成要素10.表演游戏是根据故事、 童话、 舞蹈等文艺作品的内容, 指导幼儿进行扮演的游戏 它需要背诵文学语言,在充分理解的基础上,依据作品情节,分角色表达出人物性格属于 一种特殊的角色游戏,它是对童话或故事中成型角色的语方、动作、表情等进行创造性扮演 的游戏
二、简答题1.游戏的觉悟实践的重要观点有哪些? 答游戏的觉醒理论又称内驱力理论主要观点是
(1)环境刺激是觉醒的重要源泉
(2)机体具有维持体内均衡的主动调节机制
(3)当有新异刺激机会体采用探索的方法来下降觉醒程度
(4)当缺少刺激时机体采取游戏的方式来进步觉醒水平2.经典游戏理论有哪些贡献?
①在人类历史上第一次严肃地思考并解释了儿童游戏的原因与意义;
②从儿童生理的不 同侧面对儿童游戏的原因与意义进行解释;
③从人的一般本性和共性角度对儿童游戏的原因 与意义进行解释;
④基本上肯定了游戏是儿童的一种重要活动, 是儿童心理发展的重要力量 3.简述幼儿游戏的虚构性特征 答虚构性即幼儿游戏是在假想的情景中反映实在的活动具备显明的虚构性这是游戏的一个凸起的特点,幼儿的游戏是现实生活与想象活动联合的成果游戏离不开想象,想象既不能完整脱离现实,也不能原底本本地复制现实游戏中幼儿通过扮演角色(如扮演医生看病、司机开车、售货员卖货),模拟成人的语言动作,应用各种象征性资料反映现实生活上的人和事以及彼此之间的关联 游戏的这种设想性特色,使幼儿不受详细条件的限度,不受时光和地点的制约,把设想中的情节发展下去 幼儿在游戏中 内在现实超出了外在现实 物体的日常意义被疏忽 而代替以游戏中新的意义通过象征与转换 幼儿在游戏中实现了从心理现实到社会现实的对接4.游戏性体验包括哪些主要成分
(1)兴趣性体验
(2)自主性休会
(3)胜率性体验
(4)风趣感
(5)劲力愉快5.玩具有哪些教育作用?
①玩具有利于培养幼儿科学探索的精神;
②玩具有利于培养幼儿审美能力和品德行为;
③玩具有利于幼儿认知能力的发展 6.简述幼儿游戏的认知分类
①感觉运动游戏;
②象征性游戏;
③结构游戏;
④规则游戏
三、论述题1.论述社会文化历史学派游戏理论的主要观点、贡献与局限性 社会文化历史学派也称为维鲁列学派,代表人物有维果斯基、艾里康宁等心理学家 主要观点
(1)游戏起源于社会生活;
(2)游戏不是儿童的天赋本能活动,而是发展 到一定阶段才出现的活动;
(3)游戏活动具有想象性和规则性;
(4)游戏对儿童有着巨大的 发展价值;
(5)游戏促进了儿童对角色的认识 贡献强调游戏的发展是儿童与成人相互作用的结果;赋予游戏以更为积极的重要价 值;对于学前教育实践具有重要影响 局限性一些理论观点需要进一步探讨和验证;过分夸大成人在儿童游戏中的作用2.举例论述游戏对幼儿社会性发展的促进作用
(一)游戏为幼儿提供了社会交往的机会,发展了幼儿社会交往的能力
(二)游戏有助于幼儿克服自我中心化,学会理解 他人
(三)游戏使幼儿学习社会角色,增强社会角色扮演的能力
(四)游戏有助于幼儿掌握社会行为规范,形成良好的道德品质
(五)游戏有助于幼儿增强自制力 (例子可参照教材 P55-59) 3.试论述如何在幼儿园中体现以游戏为基本活动幼儿园以游戏为基本活动对教师提出了更高的要求不仅要求教师科学.合理地安排一日生活给幼儿提供各种游戏的机会还要求教师具备发现.分析指导幼儿游戏的意识和能力变幼儿被动的学习为主动的需要.在幼儿园一日生活中尊重幼儿的年龄特征使各种活动都带有游戏的要素:1幼儿园生活活动2幼儿园教学活动3游戏活动总之实现幼儿园以游戏的形式开展教育活动完成特定的教育教学活动同时要注重开展幼儿自由的游戏活动充分发挥游戏自主性特点激发幼儿内在的活动动机产生积极体验获得身心和谐发展
4.举例说明本体性游戏和工具性游戏在幼儿园教育中具有什么作用?本体性游戏强调幼儿可以主动支配行为和自由参加游戏它反映幼儿发展的水平和兴趣爱好表演游戏和结构游戏都属于此类游戏工具性游戏强调游戏外在的工具价值即教学价值音乐游戏体育游戏智力游戏等都属于此类游戏 实际上,无论何种形式的游戏,其目的都指向幼儿的全面发展,有利于幼儿身心素质的提高作业
三一、名词解释1.轶事记录法是指简短地记录幼儿的游戏或游戏中的偶发事件这些记录可反映幼儿 的游戏技能以及社会性、认知、情感和身体等方面发展的状况2.交叉式介入法是指当幼儿有教师参与的需要或教师认为有指导的必要时,由幼儿邀 请教师作为游戏中的某一角色或教师自己扮演一个角色进入幼儿的游戏, 通过教师与幼儿角 色之间的互动,起到指导幼儿游戏的作用
3. 专门化玩具亦称成人玩具,是根据游戏的需要,专门设计制作的玩具,如各种交通 工具、炊具、娃娃等它们可直接充当游戏的成员或设备,有助于幼儿模仿成人的活动,激 发幼儿游戏的兴趣和愿望
4. 结构造型玩具如各种积木、积塑、泥、沙、雪等由于这类玩具的玩法没有定型, 幼儿根据自己的想象,可以利用这种玩具建造各种建筑物或者立体形象,对挖掘儿童智能, 培养幼儿的创造力、想象力有着重要作用,此外还能提高幼儿动作的协调性和准确性,提高 幼儿游戏的兴趣
5. 智力玩具是指用以发展幼儿智力的玩具,包括各种图片、卡片和各种拼、插、套、 镶嵌等材料
二、简答题
1. 幼儿游戏场地环境创设的原则是什么? 答第一,促进幼儿的发展;第二,符合幼儿特点;第三,保证幼儿的安全性
2. 简答教师组织教学游戏时的主要环节答 准备游戏经验,投放材料;确定游戏活动的规则和方法;观察游戏;参与游戏,指 导游戏;评价游戏,分享游戏体验
3. 如何保证游戏观察的有效性?答 观察面要广;有深度;具备一定的灵敏性
4.简述结构游戏的年龄特征答 小班开始时只是无目的的摆弄结构材料,还不会搭一般结构游戏时间为 10 分钟 中班目的比较明确,对搭建材料的动作和过程感兴趣,也关心游戏的成果一般结 构时间为 20 分钟 大班基本掌握结构的技能能围绕一个主题进行长时间的结构活动,并出现多人参与 的集体结构游戏
5.幼儿表演游戏的特点和作用是什么?答 特点游戏性、表演性 作用培养幼儿良好的品质;培养幼儿良好的行为方式;有利于发展幼儿的语言能 力 ,激发幼儿对文学艺术的兴趣
6. 如何对班级的玩教具进行管理?答 建立玩教具使用的规范;合理放置,便于幼儿取放;定期清洗、检修玩教具;根据 需要,及时增减玩具
三、论述题1.联系教育实际,论述如何评价在幼儿游戏过程中教师的指导行为参考答案教师介入的方式主要有平行式介入、交叉式介入和垂直介入教师在进行指导时,应采取语言和非语言等混合的方法对游戏行为进行指导如教师的一个微笑、一声赞美,能鼓起幼儿战胜自我的信心和战胜困难的勇气在以下特殊情况下教师可适度的介入
(1)当幼儿在游戏中因遇到困难、挫折,难以实现自己的游戏愿望时;
(2)当幼儿在游戏中有不安全的倾向时;
(3)当幼儿主动寻求帮助时;
(4)当幼儿出现过激行为时2.结合你所观察到的幼儿角色游戏,举例论述幼儿喜欢扮演什么角色?表现出什么样的行为?幼儿有怎样的心理体验?参考答案游戏中幼儿喜欢扮演妈妈、教师、司机、医生、警察等角色例如,他们会学着妈妈炒菜的样子、学警察站立不动或者指挥交通的样子、学医生给病人看病或打针的样子角色游戏是幼儿建立积极情感、调整消极情感的途径,也是表露或发泄情感的渠道在游戏中幼儿体验各种情感,如快乐、对别人的关心和同情、成功的喜悦或恐惧等,又可以控制这些情感角色游戏的一方提供消除情感的出路,减少情感上的失调,战胜情感上的障碍;另一方面以活动成功的满足,增强控制环境的能力,增长信心3.以“丢手绢”游戏为例,论述教师应如何指导幼儿规则游戏参考答案
(1)选择和编制适合幼儿年龄阶段的规则游戏;
(2)教会幼儿游戏的玩法开始前,准备几块手绢,然后大家推选一个丢手绢的人,其余的人围成一个大圆圈蹲下游戏开始,被推选为丢手绢的人沿着圆圈外行走丢手绢的人要不知不觉地将手绢丢在其中一人的身后被丢了手绢的人要迅速发现自己身后的手绢,然后迅速起身追逐丢手绢的人,丢手绢的人沿着圆圈奔跑,跑到被丢手绢人的位置时蹲下,如被抓住,则要表演一个节目,可表演跳舞、歌谣、讲故事
四、案例分析案例大班游戏“飞机场”文章略,分析如下原因1教师指导时机把握欠佳,对游戏进程引导不力表现为由于区域布置的不合理,游戏开始就出现混乱,而教师此时没有及时介入给予指导;“飞机场”的游戏多少有些超出孩子们的生活经验,故游戏过程中对“机长”的指导应该是重点,在游戏开始前就该有适当指导,以确保游戏进程顺利,但教师却是在登机后出现情况才介入;“机长”关于飞机将爆炸的说法影响了孩子们愉快的游戏心理,教师此时却没有任何反应;第一个航班“降落”后,第二个航班起飞时,孩子们已有经验,教师此时却完全介入甚至取代了孩子 原因2教师的指导语言和行为有待改进表现为以乘客身份介入后,没有用激励性语言来干预当时的混乱情景,反而给“播音员”以更大压力;在指导“机长”通知起飞时,一字一句地教给幼儿没有体现出教师与幼儿的良好互动,不利于幼儿的思维和认知主动发展;在第二个航班开始起飞时,教师完全取代幼儿自行指挥,则犯了强行控制游戏进程的大忌,达不到幼儿在创造和发现中主动发展的目的 原因3两次航班在同一区域起飞,体现出环境创设的不合理请您务必删除一下内容,O∩_∩O万分谢谢!!!2015年中央电大期末复习考试小抄大全,电大期末考试必备小抄,电大考试必过小抄IndonesiahasemergedasatopvacationdestinationforChinesethissummeralongwithThailandsPhuketislandandtheMaldivesarchipelago.EncouragedbygrowthinChinesetravelerstoIndonesiathegovernmentinJakartahasrecentlyrelaxeditsvisapolicy.SinceJune10ChinesetouristscanenterIndonesiathroughnineappointedlocationsincludingtheSoekarnoHattaInternationalAirportinJakartatheNgurahRaiInternationalAirportinBaliandtheKualaNamuInternationalAirportinMedanbyjustgettingtheirpassportsstampedonarrival.Officiallyitiscalledthefree-visascheme.ThenewpolicyalsomeansChinesetouristscansave$35onvisafeeswhichwilllikelymaketripstoIndonesiamorealluring.WhilesuchanarrangementallowsChinesevisitorstostayupto30daysforthepurposeoftravelingthoseseekingextensionswillneedtogetpaidvisasfromthatcountrysmissionsinBeijing Shanghai Guangzhou or HongKongaccordingtoanofficialattheIndonesiaembassyinBeijing.SantoDarmosumartoheadoftheembassysinformationsocialandculturalsectionsaysthenewpolicyisaimedatstrengtheningpeople-to-peoplecontactsbetweenthetwocountries.DaiYumarketingdirectorofCtripamajorChineseonlinetravelagencysays:Weveseenanearly50percentgrowthoverthepreviousmonthinthenumberofChinesetouriststoBalisincethepolicywasannounced.DuringhistriptoChinainMarchIndonesianPresidentJokoWidodoproposedthathiscountryandChinaaimtoincreasetwo-wayvisitstoamaximumof10millionpeopleinthenextfewyears.TheIndonesiangovernmenthassettheirsightsongreeting2millionChinesetouristsbytheendofthisyearaccordingtotheofficial.TheIndonesiangovernmenthopesthatIndonesiannationalswouldalsobegivenpreferentialtreatmentwhilevisitingChinasaysDarmosumarto.In2013thenumberofChinesetouristswhovisitedIndonesiastoodaround
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provinceandShanghaitoJakartaaswell.IttakesfromsixtoeighthoursonanonstopflighttoreachIndonesiafromChina.Indonesiaishometomorethan17000islands.TouristscantourYogyakartatoseePrambanamandBorobudurtwohistoricalandreligioussitesandexplorethelocalhandicraftmarkets.ThebaseofavolcanoBandungwhichisalsoknownastheParisofJavaisidealforadventure-seekers.ManyecotourismdestinationssuchasTobaLakeinSumatraTanjungPutingNationalParkinKalimantanandBunakeninManadoareplacestheembassyofficialrecommendsfortourists.Indonesiaboastsworld-classsurfingfacilitiesalongtheshoresofSumatradowntoNusaTenggaraIslands.RecentlyLombokasisterislandeastofBalihasgottensomuchattentionfromChinesetravelersthatsometravelagenciesareofferingtwinpackagesforBaliandLombok.ThebesttimetovisitBaliisfromMaytoOctoberwhenitdoesnt rain muchandtheweatheriscool.AtpresstimeaweeklongpackagefromShanghaiorGuangzhoutoBaliwasalittlemorethan3000yuan$480onCtripswebsite.ChinesetouristshavetakenashinetoraftinginUbudsightseeinginTanahLotandsurfinganddivinginNusaLembongansaysDai.CivetcoffeeessentialoilandwoodcarvingsareamongthemostpopularproductsforChinesetouristsinIndonesiashesays.Indonesianfoodisalsosomethingthatvisitorsshouldntmiss.Localcuisinesfeaturemanyspicesincludingpeppersandclovesandcoconutpulp.Friedricedirtyduckandroastsucklingpigarerecommended.Childrensillustrationbooksfirstappearedinthe1600sinEurope.TheirpassagetoChinahowevertookmuchlongerroughly300years.InChinachildrensillustrationbookshaveahistoryofjust100yearsandtheirdevelopmentcanbedividedintofourstages.Fromearly1900stomid1900salargenumberofbooksandmagazineswithillustrationsappearedwiththefastdevelopmentofthemodernpublishingindustry.Theillustration artsatthattimewereamixedgenreofChinesetraditional paintingsandthewestern styleandmostofthestoriesoriginatefromthefundamentalchangesthatChinaexperiencedafterthecollapseofQingDynasty1644-1911thewarlordstrugglesandthewaragainsttheJapaneseinvasion.Thesecondstagewasfrommid1900stolate1970swhentheculturalrevolution1966-76ended.Thefastdevelopmentofsomespecialpublishinghousesforchildrengavebirthtoalargenumberofillustration-storybookswhichmadeagooduseoffolkarttechniquessuchaswoodboardcarvingfrescoesandinkandwashpaintingetc.ManyofthepopularstoriesarefromChinesehistoryandwarsafter1900s.Thethirdstageisfromearly1980stolate1990sagoldenperiodforthedevelopmentofchildrensillustrationbooks.Thereformandopening-upbroughtinnewconceptsandideasfromtheWesttoChinaacountrythathadbeenclosedtotheWestfornearlythreedecades.Fastdevelopmentofeconomysocietyandcultureprovidedthewritersandpainterswithalotofinspirationtocreatenewliteratureworksanddrawillustrations.ChinaalsoimportedlargeamountsofchildrensillustrationbooksfromtheWestandJapan.ManyyoungparentsinChinahaveastrongnostalgiaaboutchildrensillustrationbookstheyreadinthe1980sand1990s.ThisisalsothelasterainChinasartisticinnovationbeforetheadventoftheInternetperiod.ThefourthstageisfeaturedwiththespreadoftheInternetandtheothercomputerizedmeansofartinnovation.Thehand-drawnchildrensillustrationbooksaregraduallyreplacedbycartoonsdrawnandcopiedbysoftwareandmachinesandshownontabletscomputerstelevisionandsmartphonesinsteadofbooks.HainanTropicalWildlifeParkandBotanicalGardenisnatureshavenwithnolessthan4000rarebirdsandanimalsrepresenting200species.Withtropicalforestcoveringover90percentofitsareathegardenoffersbeautifulviewsofawiderangeoftropicalplantsflowersandfruittrees.Thescenicspotabout25kilometersfromthecenterofHaikouoffersadrive-thrusafaritourwhereyoucangetupclosewithelephantslionsandbears.TheSafarionFootareafeatureswalkingtrailswherevisitorscanseetherestoftheanimalsincludinghipposandmonkeysandfeedthemforasmallfee.Visitorsalsocanseewhathappenswhenyoubreedalionandatiger.Twouniqueattractionsarerarehybrids:aligertheoffspringofamallionandafemaletigerandatigonwhichiscreatedbyafemalelionandamaletiger.Asa teachingcenteroftheNationalPopularScienceEducationprogramtheparkalsoservesasasecondclassroomforstudentstolearnaboutwildlifeandplants.Sinceitwasestablishedin1995ithasreceivedmorethanonemillionstudentvisitors.AtacrucialmomentwhenpessimismhasbroughttheGreekcrisistosuchaheadthatthecountryisclosertoadefaultonitsdebtrepaymentsthaneverLiofferedasparkofenthusiasmtorestartthestalledtalksbycallingonGreeceanditscreditorstoreachalast-minutedealthatwillallowGreecetoremainintheeurozone.GiventheescalationofthecountryscrisisovertheweekendsentashockwavethroughtheglobalstockmarketsonMondaythereareamplereasonstoworryabouttheuncertaintiessurroundingtheeventsinGreeceandtheeffectadefaultwouldhaveonEuroperelationsbetweenChinaandtheEUglobalfinancialstabilityandthenascentglobaleconomicrecovery.Greecehasannouncedthatitwillholdareferendumonabailoutplanproposedlastweekbythecountryscreditors.InresponseGreeceseurozonepartnershaverefusedtoextendthecountrysbailoutprogramandtheEuropeanCentralBankcappeditsemergencysupportforthecountrysbanks.ArealdangernowloomsofGreeceexitingtheeurowhichmightderailtheglobaleconomicrecoveryanddamagethelong-termviabilityoftheeuroasacurrency.Howeversuchatragedyisneithercertainnorunavoidable.TheEUshouldshoulderitsresponsibilitytopreventtheGreekcrisisfromovershadowingthefragileglobalrecovery.Asamajorcustomerandsupplierofthe28-nationEUandaresponsiblelong-termholderofEurobondsChinasconfidenceinandcommitmenttoastrongeurozoneoffersEUleadersthenecessarysupporttolookattheGreekcrisisfromabroaderandlongerperspective.WhenLisaidthatChinawillnotonlyconsideraChina-EUinvestmentplatformtobackEuropeanCommissionPresidentJean-ClaudeJunckersplantorevivetheEuropeaneconomybutalsobuymorebondsissuedbytheEuropeanInvestmentBankEUleadersshouldbeclearthatChinawantstoseetheEUmaintainitsintegrityandaforwardtrajectory.Suchaconfidence-buildingeffortisparticularlyvaluableespeciallyfromsuchalargecountryasChinawhichalreadyhasahugestakeandseekstofurtherexpanditinastrongeurozone.ItwillbeatragedytoallowinactionovertheGreekcrisistostandinthewayofgrowth-boostingSino-EUcooperation.请您删除一下内容,O∩_∩O谢谢!!!2016年中央电大期末复习考试小抄大全,电大期末考试必备小抄,电大考试必过小抄Acetylcholineisaneurotransmitterreleasedfromnerveendingsterminalsinboththeperipheralandthecentralnervoussystems.Itissynthesizedwithinthenerveterminalfromcholinetakenupfromthetissuefluidintothenerveendingbyaspecializedtransportmechanism.Theenzymenecessaryforthissynthesisisformedinthenervecellbodyandpassesdowntheaxontoitsendcarriedintheaxoplasmicflowtheslowmovementofintracellularsubstancecytoplasm.Acetylcholineisstoredinthenerveterminalsequesteredinsmallvesiclesawaitingrelease.Whenanerveactionpotentialreachesandinvadesthenerveterminalashowerofacetylcholinevesiclesisreleasedintothejunctionsynapsebetweenthenerveterminalandthe‘effector’cellwhichthenerveactivates.Thismaybeanothernervecelloramuscleorglandcell.Thuselectricalsignalsareconvertedtochemicalsignalsallowingmessagestobepassedbetweennervecellsorbetweennervecellsandnon-nervecells.Thisprocessistermed‘chemicalneurotransmission’andwasfirstdemonstratedfornervestotheheartbytheGermanpharmacologistLoewiin
1921.Chemicaltransmissioninvolvingacetylcholineisknownas‘cholinergic’.Acetylcholineactsasatransmitterbetweenmotornervesandthefibresofskeletalmuscleatallneuromuscularjunctions.Atthistypeofsynapsethenerveterminaliscloselyapposedtothecellmembraneofamusclefibreattheso-calledmotorendplate.Onreleaseacetylcholineactsalmostinstantlytocauseasequenceofchemicalandphysicaleventsstartingwithdepolarizationofthemotorendplatewhichcausecontractionofthemusclefibre.Thisisexactlywhatisrequiredforvoluntarymusclesinwhicharapidresponsetoacommandisrequired.Theactionofacetylcholineisterminatedrapidlyinaround10milliseconds;anenzymecholinesterasebreaksthetransmitterdownintocholineandanacetateion.Thecholineisthenavailableforre-uptakeintothenerveterminal.Thesesameprinciplesapplytocholinergictransmissionatsitesotherthanneuromuscularjunctionsalthoughthestructureofthesynapsesdiffers.Intheautonomicnervoussystemtheseincludenerve-to-nervesynapsesattherelaystationsgangliainboththesympatheticandtheparasympatheticdivisionsandtheendingsofparasympatheticnervefibresonnon-voluntarysmoothmuscletheheartandglandularcells;inresponsetoactivationofthisnervesupplysmoothmusclecontractsnotablyinthegutthefrequencyofheartbeatisslowedandglandssecrete.Acetylcholineisalsoanimportanttransmitteratmanysitesinthebrainatnerve-to-nervesynapses.Tounderstandhowacetylcholinebringsaboutavarietyofeffectsindifferentcellsitisnecessarytounderstandmembranereceptors.Inpost-synapticmembranesthoseofthecellsonwhichthenervefibresterminatetherearemanydifferentsortsofreceptorsandsomearereceptorsforacetylcholine.Theseareproteinmoleculesthatreactspecificallywithacetylcholineinareversiblefashion.Itisthecomplexofreceptorcombinedwithacetylcholinewhichbringsaboutabiophysicalreactionresultingintheresponsefromthereceptivecell.Twomajortypesofacetylcholinereceptorsexistinthemembranesofcells.Thetypeinskeletalmuscleisknownas‘nicotinic’;inglandssmoothmuscleandthehearttheyare‘muscarinic’;andtherearesomeofeachtypeinthebrain.ThesetermsareusedbecausenicotinemimicstheactionofacetylcholineatnicotinicreceptorswhereasmuscarineanalkaloidfromthemushroomAmanitamuscariamimicstheactionofacetylcholineatthemuscarinicreceptors.Acetylcholineistheneurotransmitterproducedbyneuronsreferredtoascholinergicneurons.Intheperipheralnervoussystemacetylcholineplaysaroleinskeletalmusclemovementaswellasintheregulationofsmoothmuscleandcardiacmuscle.Inthecentralnervoussystemacetylcholineisbelievedtobeinvolvedinlearningmemoryandmood.AcetylcholineissynthesizedfromcholineandacetylcoenzymeAthroughtheactionoftheenzymecholineacetyltransferaseandbecomespackagedintomembrane-bound vesicles .Afterthearrivalofanervesignalattheterminationofanaxonthevesiclesfusewiththecellmembranecausingthereleaseofacetylcholineintothe synapticcleft .Forthenervesignaltocontinueacetylcholinemustdiffusetoanothernearbyneuronormusclecellwhereitwillbindandactivatea receptor protein.Therearetwomaintypesofcholinergicreceptorsnicotinicandmuscarinic.Nicotinicreceptorsarelocatedatsynapsesbetweentwoneuronsandatsynapsesbetweenneuronsandskeletalmusclecells.Uponactivationanicotinicreceptoractsasachannelforthemovementofionsintoandoutoftheneurondirectlyresultingin depolarization oftheneuron.Muscarinicreceptorslocatedatthesynapsesofnerveswithsmoothorcardiacmuscletriggerachainofchemicaleventsreferredtoassignaltransduction.Foracholinergicneurontoreceiveanotherimpulseacetylcholinemustbereleasedfromthereceptortowhichithasbound.Thiswillonlyhappeniftheconcentrationofacetylcholineinthesynapticcleftisverylow.Lowsynapticconcentrationsofacetylcholinecanbemaintainedviaahydrolysisreactioncatalyzedbytheenzymeacetylcholinesterase.Thisenzymehydrolyzesacetylcholineintoaceticacidandcholine.Ifacetylcholinesteraseactivityisinhibitedthesynapticconcentrationofacetylcholinewillremainhigherthannormal.Ifthisinhibitionisirreversibleasinthecaseofexposuretomanynervegasesandsomepesticidessweatingbronchialconstrictionconvulsionsparalysisandpossiblydeathcanoccur.Althoughirreversibleinhibitionisdangerousbeneficialeffectsmaybederivedfromtransientreversibleinhibition.DrugsthatinhibitacetylcholinesteraseinareversiblemannerhavebeenshowntoimprovememoryinsomepeoplewithAlzheimersdisease.abstractexpressionismmovementofabstractpaintingthatemergedinNewYorkCityduringthemid-1940sandattainedsingularprominenceinAmericanartinthefollowingdecade;alsocalledactionpaintingandtheNewYorkschool.ItwasthefirstimportantschoolinAmericanpaintingtodeclareitsindependencefromEuropeanstylesandtoinfluencethedevelopmentofartabroad.ArshileGorkyfirstgaveimpetustothemovement.HispaintingsderivedatfirstfromtheartofPicassoMiróandsurrealismbecamemorepersonallyexpressive.JacksonPollocksturbulentyetelegantabstractpaintingswhichwerecreatedbyspatteringpaintonhugecanvasesplacedonthefloorbroughtabstractexpressionismbeforeahostilepublic.WillemdeKooningsfirstone-manshowin1948establishedhimasahighlyinfluentialartist.Hisintenselycomplicatedabstractpaintingsofthe1940swerefollowedbyimagesofWomangrotesqueversionsofbuxomwomanhoodwhichwerevirtuallyunparalleledinthesustainedsavageryoftheirexecution.PainterssuchasPhilipGustonandFranzKlineturnedtotheabstractlateinthe1940sandsoondevelopedstrikinglyoriginalstyles—theformerlyricalandevocativethelatterforcefulandboldlydramatic.OtherimportantartistsinvolvedwiththemovementincludedHansHofmannRobertMotherwellandMarkRothko;amongothermajorabstractexpressionistsweresuchpaintersasClyffordStillTheodorosStamosAdolphGottliebHelenFrankenthalerLeeKrasnerandEstebanVicente.Abstractexpressionismpresentedabroadrangeofstylisticdiversitywithinitslargelythoughnotexclusivelynonrepresentationalframework.ForexampletheexpressiveviolenceandactivityinpaintingsbydeKooningorPollockmarkedtheoppositeendofthepolefromthesimplequiescentimagesofMarkRothko.Basictomostabstractexpressionistpaintingweretheattentionpaidtosurfacequalitiesi.e.qualitiesofbrushstrokeandtexture;theuseofhugecanvases;theadoptionofanapproachtospaceinwhichallpartsofthecanvasplayedanequallyvitalroleinthetotalwork;theharnessingofaccidentsthatoccurredduringtheprocessofpainting;theglorificationoftheactofpaintingitselfasameansofvisualcommunication;andtheattempttotransferpureemotiondirectlyontothecanvas.Themovementhadaninestimableinfluenceonthemanyvarietiesofworkthatfolloweditespeciallyinthewayitsproponentsusedcolorandmaterials.ItsessentialenergytransmittedanenduringexcitementtotheAmericanartscene.。