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本文用 H-600型透射电子显微镜观察了6例眙儿大脑皮层枕极245个突触的超微结构,结果表明在4.5个月胎儿枕极大脑皮层未见到突触,在5个月胎儿仅观察到少量突触,以后随胎龄的增加,突触数逐渐增多。在六个月以后胎儿大脑皮层,突触数明显增多,在新观察到的245个突触中,次轴树突触占绝大多数,占胎儿突触观察总数的77.6%。其次为轴棘突触,占胎儿突触观察总数的4.5%,从五个月胎脑开始观察到轴极突触,且这些轴棘突出的后成分中均不含有棘器。另外在胎儿枕极皮层,还观察到较多的轴-体突触,占胎儿突触观察总数的3.7%。此外,尚见到少量轴-轴,树-树,树-棘突触和串,并联突触。 相似文献
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本文应用HRP逆行追踪法在电镜水平上对猫丘脑中央外侧核内皮质投射神经元的超微结构及其突触联系首次进行了研究,该核内皮质投射神经元以中型多见,胞核较大,核仁清晰,偏位,核膜有凹陷,常染色质较多,胞质内含丰富的线粒体、游离核糖体和粗面内质网,标记树突直径变化较大,从0.68μm到4.4μm,含较多的线粒体、微管及滑面内质网,未见突触小泡,标记的皮质投射神经元胞体和树突做为突触后成份,与非标记的突触前成份形成下列突触:①轴-树突触,突触前轴突终末以SR型和F型居多;②轴-体突触,突触前终末中有F型和RF型;③树-树突触;④轴-轴-树突触;⑤突触复合体,许多标记树突做为中央树突参与形成汇聚型突触复合体。 相似文献
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本文应用顺行溃变的方法,首次在电镜水平对猫丘脑中央外侧内脊丘系终末的超微结构和突触联系进行了研究。在横断第四脊髓颈节一侧的外侧索和部分前索4-5天后,电镜下发现在损毁同侧的丘脑中央外侧核的中段和尾段,均有少量的溃变终末。脊丘系溃变的轴突终末有两种形式:电子致密型和电子透明型,以电子致密型多见。溃变的脊丘系终末大小形态各异,主要含大量密集的圆形突触小泡。根据小泡形状和终末大小的差异,溃变终末可分以下两型:SR型占82.5％;LR型占17.5％。溃变轴突终末主要与树突形成不对称型轴——树突触,个别的突触后树突含突触小泡。溃变轴突终末多参与形成以树突为中心的汇聚型突触复合体。在由溃变轴突终末与树突所形成的轴——树突触中,有42.5％的数量位于突触复合体内。偶尔见到溃变轴突终末参与形成的轴-轴-树突触。 相似文献
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为确立后索核内初级传入终末与丘脑投射神经元间的突触联系,本文采用顺行溃变与 HRP 逆行追踪相结合的方法,在电镜水平对后索核内初级传入终末与丘脑投射神经元间的突触联系组合形式进行了研究。结果表明,后索核内有6种突触联系形式:(1)溃变轴突终末与 HRP 标记树突形成轴—树突触;(2)溃变轴突终末与 HRP 标记胞体形成轴—体突触;(3)溃变轴突终末及正常轴突终末与标记的中央树突形成汇聚型突触复合体;(4)轴—轴—树连续性突触;(5)溃变轴突终末与非标记树突形成轴—树突触;(6)非溃变的含扁平小泡或多形态小泡轴突终末与 HRP 标记的神经元胞体形成轴—体突触.本研究首次报道了猫后根初级传入终末与后索核丘脑投射神经元间的直接突触联系。突触形式计有轴—树和轴—体突触及以树突为中心的突触复合体.本研究结果为阐明后索核内非伤害性信息传递与整合的作用方式提供了直接的突触学基础。 相似文献
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用顺行溃变方法对猫后索核内后根初级传入纤维终末的超微结构和突触联系进行了研究。在切断C_4-T_1和L_4-S_1脊神经后根3～4天后,电镜下发现后索核内有三种溃变终末,出现最多的是电子致密型溃变,此外,也观察到了少量的神经微丝型溃变和电子透明型溃变。溃变的初级传入终末多数较大,含有圆形突触小泡。溃变初级传入终末作为突触前成分主要与后索核内的树突形成轴-树突触,而轴-体突触和轴-轴突较少。此外,还观察到溃变轴突终末参与形成突触复合体。 相似文献
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本文应用顺行溃变和 HRP 逆行追踪相结合的方法,首次在电镜水平对猫丘脑中央外侧核内脊丘系终末与丘脑皮质投射神经元之间的突触联系进行了研究.首次发现在丘脑中央外侧核内,脊丘系终末与该核内投射至前乙状回的神经元及投射至前上薛氏回和中上薛氏回前端的神经元之间,形成直接的轴—树突触联系。为脊髓—丘脑中央外侧核—皮质通路的确立提供了有价值的突触学证据.此外,在中央外侧核内,脊丘系终末和丘脑皮质投射神经元还分别与其它突触成份形成突触联系.本文研究结果为丘脑痛觉整合作用机制的研究,为神经外科痛治疗中的板内核损毁理论提供有价值的形态基础。 相似文献
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本文应用辣根过氧化物酶(HRP)逆行追踪技术与电镜相结合的方法,对猫后索核丘脑投射神经元的分市及超微结构进行了研究。结果表明,后索核丘脑投射神经元主要分布于后索核中段,尾侧段次之,嘴侧段最少。标记神经元均出现于HRP注射部位的对侧后索核内,主要为中等园形细胞。电镜下,神经元胞核较大,核膜光滑或有凹陷,常染色质较多,异染包质1较少,胞浆丰富,含有大量的游离核糖体,粗面内质网及线粒体。标记的丘脑投射神经元胞体和树突可以作为突触后成分与轴突形成轴一体突触和轴一树突触;标记神经元胞体还可以和突触前树突形成树一体突触;标记的树突做为中央成分与多个轴突形成汇聚型突触复合体。此外,还发现标记的胞体和树突与非标记的树突之间的非突触的粘着斑连接。 相似文献
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为什么0～3岁这个阶段如此重要?1.幼儿大脑突触密度的变化。2.大脑在出生的时候只发育完成了25%,但是到三岁末的时候已经发育完成了90%,"在生命的头三年里,突触的数量以惊人的速度增长。在3~10岁的时间里,儿童大脑里的突触数量是成人的两倍,这也证明了儿童头几年里为何能快速的学习。" 相似文献
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棘腹蛙与棘侧蛙的外形区别及食物分析 总被引：1，自引：0，他引：1
王云 《黔南民族师范学院学报》2003,23(6):64-67
于2000—2001年间，对榕江县计划乡的棘腹蛙和棘侧蛙进行了观察和研究，初步了解了二者之间的外形区别及其食物种类，食物对象主要以昆虫为主，涉及到昆虫纲的10个目、22个科，除此之外，部分节肢动物、环节动物、也是其食物对象。 相似文献
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Peng Shaohu 《大连大学学报》1993,(1)
采用适用于石蜡切片的新近发展的抗体,对20例在临床病理上符合恶性组织细胞增生症(简称恶组)特点的病例进行了其细胞属性的探讨.发现大多数病例的瘤细胞为组织细胞起源的可能性大;5例肠型恶组,其中4例瘤细胞表达 T 细胞标记,表明其应归属于 T 淋巴细胞系列肿瘤;另一例肠型恶组表达组织细胞标记,可能代表真正的组织细胞源性的肠型恶组;此外,初步观察表明除肉芽肿样型外恶组的其它三种病理组织学类型间无明显免疫组化表型的不同. 相似文献
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《College Teaching》2013,61(4):113-115
Ph.D. programs train students to perform quality research but not necessarily to deliver quality undergraduate instruction. For students who want to develop such skills, and for universities interested in creating programs to combine broad disciplinary instruction with specialization in effective pedagogical practices, there is a Ph.D. alternative—the Doctor of Arts (D.A.). The D.A. is regarded as a Ph.D. equivalent and aims to better train students to be effective educators since the majority of academic positions are located at primarily undergraduate institutions, with substantially more faculty time consumed by teaching duties than research. A significant difference between traditional Ph.D. and D.A. students is the latter engage in scholarship of teaching and learning, through both topical seminars and participation in supervised teaching internships. Thirty years of job placement statistics gathered from Idaho State University D.A. programs indicate that graduates are well qualified to enter into faculty positions at a wide range of higher education institutions. 相似文献
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在溴化十六烷基三甲基铵存在下碘化钾——结晶紫体系浮选分离镉的研究 总被引：2，自引：0，他引：2
研究了在溴化十六烷基三甲基铵存在下碘化钾—结晶紫体系浮选分离镉的行为及其与常见离子分离的条件。试验表明,在一定条件下,能使Cd(Ⅱ)与常见离子Zn(Ⅱ)、Fe(Ⅲ)、Co(Ⅱ)、Ni(Ⅱ)、Mn(Ⅱ)、Al(Ⅲ)分离。 相似文献
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《英语广场》2014,(9)
Oscar Wilde is a brilliant Irish dramatist, novelist and critic. His only novel ― The Picture of Dorian Gray— is one of the most influential works by Wilde. This paper aims to study the paradox of the three main characters' life in this novel through close reading in order to achieve a better understanding of this controversial book. 相似文献
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Intake interviews were analyzed from 365 adults molested as children (AMACs). The AMACs were entering treatment at the Child Sexual Abuse Treatment Program (San Jose, CA). This study presents data on the relationship of the perpetrator to the victim, and whether most molestations include intercourse. The majority of the perpetrators (62%) were either biological fathers or father-surrogates. Ninety-nine percent of the perpetrators were known to the victim; 97% were male. As in past studies, fondling from the waist down was the most common type of molestation, occurring in 92% of the cases. Forty-four percent of cases included intercourse. The present findings are compared with past research and are discussed in the context of common misconceptions associated with child sexual abuse. 相似文献
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In this study, 69 women were surveyed who, as a result of a prenatal screening knew they were at risk for carrying a fetus with a disability. Results indicated that most women were referred by their physicians for genetic counseling either because of their age or because of an abnormal blood test. The majority of women indicated they would choose to terminate a pregnancy that tested positive for a disability, but the type of disability of the fetus, either Down syndrome or spina bifida, made no difference in the decision that women believed they would make. The women's intention to terminate a pregnancy appeared to be unrelated to their overall knowledge about disabilities but was negatively related to their knowledge of disability-related services. Although women reported that genetic counseling was helpful, they revealed that they were not given information about future-quality-of-life issues for individuals with disabilities nor provided with the positive as well as the negative aspects of giving birth to a child with disabilities. 相似文献