实验四 蟾蜍心脏传导系、心脏起搏点分析;蟾蜍循环系统的解剖

实验四 蟾蜍心脏传导系、心脏起搏点分析;蟾蜍循环系统的解剖 实验四 蟾蜍心脏传导系、心脏起搏点分析;蟾蜍循环系统的解剖 一(实验目的 1.练习双毁髓法，熟练掌握双毁髓技术。 2.重复练习并熟练掌握蟾蜍的解剖技术。 3.观察蟾蜍的心脏，辨认和心脏相连的血管，并学会画和心脏相连的血管的图。 4.学习双穿线手法使心脏游离。 5.学会心脏搏跳的技术方法。 6.观察蟾蜍的心血管系统，了解两栖类心脏的构造、循环途径及其特点。 二(实验原理 1.双毁髓法麻醉蟾蜍:用金属毁髓针破坏蟾蜍的脑和脊髓，使蟾蜍处于一种麻醉状态，四肢瘫软，从而对蟾蜍进行解剖，露出其心脏。通过对心脏结扎使心脏游离，阻碍循环系统由此可以观察静脉血管。 2.两栖类心脏的起搏和传导系统有静脉窦，窦房沟，房室沟组成。这一类起搏传导系统具有自动节律性，但是各部分的自动节律并不相同，其中静脉窦氏主要起搏点，它的节律性最高，正常情况下心脏的波动频率和静脉窦的节律相同(即取决于静脉窦的节律)，窦房沟和房室沟是潜在的起搏点，正常状态下他们只起传导兴奋的作用，其自身的自动节律性被主要起搏点的节律所掩盖。因此他们波动的顺序是:静脉窦先波动，然后是心房最后是心室。但是当主要起搏点的兴奋不能传导到窦房沟和房室沟的时候，他们的自动节律可引起心脏的波动。本实验用斯氏结扎法结扎蟾蜍主要和次要起搏点，观察他们的自动节律性。 3.蛙心的结构示意图 4.斯氏结扎图 coupling Centre shall be checked, the second poured concrete strength of more than 70%. In the process of reaming or boring, apart from the special provisions in factory, does not allow any work that may affect the coupling Centre, such as irrigation, to cylinder connections to flood the condenser pipes and so on. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Mounting bolts should be added lubricants, typing gently with a small hammer, not too loose or too tight, packed the bolts with the corresponding seal screw hole should be marked. 6.4.5.4.2 coupling reamed and pairings is close to the diameter of bolt bearing good hinge holes, dressed with a good two coupling bolts before you can move the rotor, boring-reaming hole in turn. Coupling bolts must be tight coupling is symmetrical diameter, in boring, reaming, two bolts out. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Due to the coupling bolts in accordance with hinge holes corresponding to the diameter of the screw holes one by one after processing, processing back bolt installation location cannot be changed, so according to bolt after the actual weight difference of nut and lock washer to match. General requirements for coupling two symmetrical diameter bolt, nut and lock washer's total weight difference should not be greater than 10 g and knocks stamped mark. (See Figure 18) The coupling bolts apply lubricant, and then gently with copper home, not too loose or too tight. Bolt Assembly is finished, symmetrical tightening all bolts to 30%, 50%, 70%, 100% force, and check the coupling flutter and before connecting the circle gradually changes its value should be less than 0.02mm. Tightening torque of the coupling bolts shall comply with the technical requirements manufacturers drawings, with a dynamometric wrench or log tension tools. Three wheel rotor swing test coupling connections should be checked: taking leave, (A处为斯氏第一次结扎部位，B为斯氏第二次结扎部位) 三(动物器材 1.动物:蟾蜍一只 2.实验仪器:手术刀两把，普通剪刀一把，解剖针一根，蜡盘两个(一个中央有圆孔)，镊子两把，大头针若干个。 四(实验步骤 1.双毁髓麻醉蟾蜍:左手食指与中指、无名指与小指分别夹着前肢、后肢，握住蛙体，拇指按住吻端使头部上下活动，两耳后腺间出现一道褶线，此线中点或用金属毁髓针沿头背中线向后移动触到一凹陷处，即枕骨大孔。拇指下压使头前俯与脊柱相连处凸起，同时将毁髓针由凹陷处垂直刺入1mm，再将针从枕骨大孔向前平行刺入颅腔并在颅腔内搅动，彻底捣毁脑组织使之成为“脊蛙”。 2.将剪开体壁的蛙体腹面向上置于解剖盘中，展开四肢，用蛙钉向内斜呈45度角于腕掌部和附跖部钉入将蛙固定于解剖盘中。骨背面的围心腔内跳动的心脏，用镊子从剪刀处提起并剪开半透明围心膜，轻轻按压即可使心脏暴露于心包腔之外。 3.找到心脏周围与之相连的血管并辨别心脏相连血管，观察各个血管之间的联系与血流方向并作好记录。 4.将蟾蜍的肝脏翻开，可见肝脏后肠系膜内有一条短而粗的血管，即肝门静脉进入肝。由肝门静脉出发，追踪与之汇合的血管并作好记录。 5.用镊子在左右动脉干下穿一线，并将心尖翻向头端，暴露心脏背面，可见三角形静脉窦与心房相连，将该线在白色的窦房沟处做斯氏第1结扎，可见心房，心室立即停止跳动，而静脉窦继续搏动。待心房和心室恢复搏动后，在冠状沟处穿线做斯氏第二次结扎。这时心房和静脉窦仍继续搏动，心室则停止搏动。 五(实验结果 coupling Centre shall be checked, the second poured concrete strength of more than 70%. In the process of reaming or boring, apart from the special provisions in factory, does not allow any work that may affect the coupling Centre, such as irrigation, to cylinder connections to flood the condenser pipes and so on. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Mounting bolts should be added lubricants, typing gently with a small hammer, not too loose or too tight, packed the bolts with the corresponding seal screw hole should be marked. 6.4.5.4.2 coupling reamed and pairings is close to the diameter of bolt bearing good hinge holes, dressed with a good two coupling bolts before you can move the rotor, boring-reaming hole in turn. Coupling bolts must be tight coupling is symmetrical diameter, in boring, reaming, two bolts out. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Due to the coupling bolts in accordance with hinge holes corresponding to the diameter of the screw holes one by one after processing, processing back bolt installation location cannot be changed, so according to bolt after the actual weight difference of nut and lock washer to match. General requirements for coupling two symmetrical diameter bolt, nut and lock washer's total weight difference should not be greater than 10 g and knocks stamped mark. (See Figure 18) The coupling bolts apply lubricant, and then gently with copper home, not too loose or too tight. Bolt Assembly is finished, symmetrical tightening all bolts to 30%, 50%, 70%, 100% force, and check the coupling flutter and before connecting the circle gradually changes its value should be less than 0.02mm. Tightening torque of the coupling bolts shall comply with the technical requirements manufacturers drawings, with a dynamometric wrench or log tension tools. Three wheel rotor swing test coupling connections should be checked: taking leave, 动脉圆锥 肝门静脉 心室 左心房 右心房 静脉窦 前腔静脉 后腔静脉 六(实验结论 1)心脏部分: 1.蟾蜍的心脏位于体腔的前部，在后胸骨下方，肝脏腹面的正中线。心脏和体腔完全隔离，外有囊状心包包裹。心包具有两层囊壁，外面的一层和体腔为界，称为壁层，其表面含有金光闪烁的色素。心包内层靠近心脏，称为脏层，coupling Centre shall be checked, the second poured concrete strength of more than 70%. In the process of reaming or boring, apart from the special provisions in factory, does not allow any work that may affect the coupling Centre, such as irrigation, to cylinder connections to flood the condenser pipes and so on. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Mounting bolts should be added lubricants, typing gently with a small hammer, not too loose or too tight, packed the bolts with the corresponding seal screw hole should be marked. 6.4.5.4.2 coupling reamed and pairings is close to the diameter of bolt bearing good hinge holes, dressed with a good two coupling bolts before you can move the rotor, boring-reaming hole in turn. Coupling bolts must be tight coupling is symmetrical diameter, in boring, reaming, two bolts out. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Due to the coupling bolts in accordance with hinge holes corresponding to the diameter of the screw holes one by one after processing, processing back bolt installation location cannot be changed, so according to bolt after the actual weight difference of nut and lock washer to match. General requirements for coupling two symmetrical diameter bolt, nut and lock washer's total weight difference should not be greater than 10 g and knocks stamped mark. (See Figure 18) The coupling bolts apply lubricant, and then gently with copper home, not too loose or too tight. Bolt Assembly is finished, symmetrical tightening all bolts to 30%, 50%, 70%, 100% force, and check the coupling flutter and before connecting the circle gradually changes its value should be less than 0.02mm. Tightening torque of the coupling bolts shall comply with the technical requirements manufacturers drawings, with a dynamometric wrench or log tension tools. Three wheel rotor swing test coupling connections should be checked: taking leave, 不含色素。从心脏外形看，整个心脏分为两个心房和一个心室，略呈圆锥形，椎尖指向后方。两心房壁较心室壁薄。心室肌较厚，富有伸缩力。心房和心室之间以冠状沟为界，右心房的位置偏于腹面，左心房的位置稍偏于背面。在心脏背面，有一个三角形的囊管，称为静脉窦，是心脏的起搏点。静脉窦前面的两角各连着一根前腔静脉，后面一只角上连着1根后腔静脉。全身各部分的静脉血液经此三条墙腔静脉汇集于静脉窦中，然后再流入右心房。 2.心脏内具有特殊的构造，使血液只能循单一的方向流动。将心房和心室的腹壁切开，可见左右心房之间有一房间隔，将两个心房完全隔开，房间隔的厚度比两个心房壁还要薄，且略倾斜，是右心房比左心房稍大。房间隔后缘是游离着的。在右心房的背壁靠近房间隔的部位，有一个窦房孔，静脉窦的血液由此进入右心房，孔口呈椭圆形，前后两边各有一片唇状瓣膜，瓣膜超心房方向开启。当心房收缩的时候，瓣膜关闭，防止血液回流至静脉窦。左心房内靠近房间隔的背壁，较窦房孔的位置稍微向前，有一个圆形孔，它是肺静脉向着左心房的入口。此处无瓣膜，由于孔道斜穿左心房壁，左心房收缩时候的压力可以使其立即关闭，也可以阻止血液倒流回肺静脉。 3.心室比两个心房都要大，外形像倒转过来的圆锥体，朝向后面的椎尖叫做心尖。在心室中央有一个空腔，周围是厚的心肌构成的心室壁，心尖部位的肌肉最厚。心室壁的内层结构疏松，状如海绵，向腔的一面具有很多细长的肌肉隆起，将内层分割成为许多裂缝状的小室，处处都和中央的空腔相通。此结构可以减少血液在心室内的混合程度。蟾蜍心室内层的这种结构不是真正的室壁结构。心室基部有一大孔称为房室孔。该孔和左右两心房相通，孔周围有四片瓣膜，腹背两面各一大片，左右两侧各一小片。瓣膜的游离缘都在心室腔内，并受到心室内壁上许多细丝状腱牵拉，当心室收缩时，各瓣膜的游离缘只能闭合，不能反转到心室中去，防止血液倒流。房间隔的游离缘一直到达房室孔处，将孔口分成两部分，是左右心房的血液各循一次，分别心室中。 2)静脉系统 静脉是引导身体各部分微血管中血液回流到心脏的血管。粗大的静脉管中具有瓣膜，并想着血液单一的方向开启，钢之血液倒流。 1.肺静脉:集中左右肺囊的细小静脉，成为左右两肺静脉，筋脉沿两肺囊内测移行，至心脏附近两肺静脉合成一支，直接进入左心房 2.前腔静脉:共一对，左右对称，分别接受同侧头部，躯干和前肢的血液，然后进入三角形的静脉窦前段两犄角中。每根前腔静脉由三大支流(颈外静脉，无名静脉，锁骨下静脉)汇集而成。 3.后腔静脉整个静脉系统中最粗大的一支。后端自两肾之间，接受肾脏，生殖器官和后肢的血液，向前移行，从肝的背面穿过接受肝的血液，一直通入静脉窦的后角。后腔静脉的主要分支有肝静脉，肾静脉和生殖腔静脉。 4.肝静脉:左右各一根，从肝脏通出，开口于后腔静脉接近静脉窦的部位 5.肾静脉:从两个肾脏通出，每侧4-6不等，不一定对称，每根各自通入后腔静脉或者两侧相对的两根先行汇合后再进入后腔静脉。在肾静脉的前段，从后腔静脉的每边又常接受一根或者两根从脂肪体通过来的支脉。 6.门静脉:指来自内脏和身体后部的血液入肝或肾以后，先分散成许多微血管，然后汇集起来，流入后腔静脉。 7.肾门静脉系:来自后肢的血液主要沿着两条静脉回心。一是位于后肢外侧的股静脉，其二是位于后肢内测的臀静脉。这两条粗大的静脉在接近骼关节的coupling Centre shall be checked, the second poured concrete strength of more than 70%. In the process of reaming or boring, apart from the special provisions in factory, does not allow any work that may affect the coupling Centre, such as irrigation, to cylinder connections to flood the condenser pipes and so on. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Mounting bolts should be added lubricants, typing gently with a small hammer, not too loose or too tight, packed the bolts with the corresponding seal screw hole should be marked. 6.4.5.4.2 coupling reamed and pairings is close to the diameter of bolt bearing good hinge holes, dressed with a good two coupling bolts before you can move the rotor, boring-reaming hole in turn. Coupling bolts must be tight coupling is symmetrical diameter, in boring, reaming, two bolts out. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Due to the coupling bolts in accordance with hinge holes corresponding to the diameter of the screw holes one by one after processing, processing back bolt installation location cannot be changed, so according to bolt after the actual weight difference of nut and lock washer to match. General requirements for coupling two symmetrical diameter bolt, nut and lock washer's total weight difference should not be greater than 10 g and knocks stamped mark. (See Figure 18) The coupling bolts apply lubricant, and then gently with copper home, not too loose or too tight. Bolt Assembly is finished, symmetrical tightening all bolts to 30%, 50%, 70%, 100% force, and check the coupling flutter and before connecting the circle gradually changes its value should be less than 0.02mm. Tightening torque of the coupling bolts shall comply with the technical requirements manufacturers drawings, with a dynamometric wrench or log tension tools. Three wheel rotor swing test coupling connections should be checked: taking leave, 部位有骼横静脉相连接。股静脉在到达后肢基部有分成内外两支:内肢为盆静脉，通向腹正中线，外肢为骼静脉，前行不远，即与臀静脉会合臀门静脉。肾门静脉到达肾脏的外缘，又接受一支从体壁来的背腰静脉，然后分出许多小支，一直延伸到肾脏内部，并分散成为微血管。 8.肝门静脉系:大部分后肢中的血液都经肾门静脉返回西藏，只有一小部分由肝运转。此外各内脏的血液也大部分先运入肝中，这样便构成肝门静脉系。 9.腹静脉:由股静脉所分出的内肢即盆静脉，左右两支在躯干后端正中线处合成。腹静脉沿体壁腹正中线前行，到达肝脏腹面的时候即离开体壁而转入体腔深部，分成两支进入肝的左右叶内。腹静脉进入肝脏前，还接受膀胱静脉，体壁静脉和心静脉。 10.肝门静脉:是汇集自胃胰脾肠等静脉而成的。肝门静脉移行只肝脏附近时，和腹静脉合并入肝，此外肝门静脉还有分支单独入肝。 七(问解答 1.第一斯氏结扎后和第二斯氏结扎后的心室搏动频率是否相同,为什么, 不相同。第一斯氏结扎后心室的搏动是受心房激动，搏动频率与心房的搏动频率相同。第二次斯氏结扎后，是心室自身的潜在兴奋性作用，使其开始搏动，不受心房控制。 2.为什么说两栖类的循环系统为不完全双循环, 心脏由两个心房，一个心室，静脉窦和动脉圆锥构成。心房内出现完全或不完全房间隔形成左心房(接受从肺静脉返回的多氧血)和右心房(从体静脉返回的缺氧血以及皮静脉返回的多氧血)，心室内壁具肌肉小梁，且和动脉圆锥中的螺旋瓣能够对血液进行分流。但由于心室不分隔.多氧血和缺氧血不能完全分开，所以这种循环是不完全的。 3.两栖类循环系统上哪些特征表现出对陆生的适应, 1)裸露但有轻微角质化的皮肤: 皮肤较薄.由多层细胞组成的表皮和真皮组成，皮肤表面处于裸露状态，并已coupling Centre shall be checked, the second poured concrete strength of more than 70%. In the process of reaming or boring, apart from the special provisions in factory, does not allow any work that may affect the coupling Centre, such as irrigation, to cylinder connections to flood the condenser pipes and so on. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Mounting bolts should be added lubricants, typing gently with a small hammer, not too loose or too tight, packed the bolts with the corresponding seal screw hole should be marked. 6.4.5.4.2 coupling reamed and pairings is close to the diameter of bolt bearing good hinge holes, dressed with a good two coupling bolts before you can move the rotor, boring-reaming hole in turn. Coupling bolts must be tight coupling is symmetrical diameter, in boring, reaming, two bolts out. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Due to the coupling bolts in accordance with hinge holes corresponding to the diameter of the screw holes one by one after processing, processing back bolt installation location cannot be changed, so according to bolt after the actual weight difference of nut and lock washer to match. General requirements for coupling two symmetrical diameter bolt, nut and lock washer's total weight difference should not be greater than 10 g and knocks stamped mark. (See Figure 18) The coupling bolts apply lubricant, and then gently with copper home, not too loose or too tight. Bolt Assembly is finished, symmetrical tightening all bolts to 30%, 50%, 70%, 100% force, and check the coupling flutter and before connecting the circle gradually changes its value should be less than 0.02mm. Tightening torque of the coupling bolts shall comply with the technical requirements manufacturers drawings, with a dynamometric wrench or log tension tools. Three wheel rotor swing test coupling connections should be checked: taking leave, 出现蜕皮现象，真皮较厚而致密.表现出陆生动物真皮的特征。 2)呼吸的多样化: a.肺呼吸:具一对结构还十分简单囊状的肺(陆地脊椎动物的重要特征)。肺囊壁具有丰富的毛细血管。由肺动脉将回心脏的缺氧血送入肺，而由肺静脉将交换后的多氧血送出肺部返回左心室。由于没有胸廓，其呼吸动作借助于口咽腔底部的升降，将空气压入肺部来完成呼吸动作(咽式呼吸)。与肺呼吸相适应的是内鼻孔的出现，声带位于肺前部，短的喉头气室中(陆生脊椎动物特征之一)。 b.皮肤呼吸:皮肤湿润，皮下血管丰富，尤其在冬季蛰眠期，皮肤呼吸对生命继续起着重要作用.。 3)不完全的双循环(由于肺呼吸的出现.循环系统发生相应的显著变化.不完全双循环和体动脉内含有混合血液是两栖类的特征) 4)支持和运动系统已基本具备陆生动物的模式: a.脊柱有了较大的分化，首次出现了一块颈椎和荐椎(具有颈椎和荐椎是陆生动物的特征)。使整个脊柱分为颈椎，躯干椎，荐椎和尾椎(愈合形成棒状的尾杆骨)四部分。颈椎与头骨的枕骨髁(1对)相关节，从而头部有了上下运动的可能性,荐椎与腰带的髂骨连接。从而后肢获得了稳固的支持。 b.首次出现了胸骨，但成体无肋骨。 c.头骨已脱离了肩带的束缚，数块骨片丢失或愈合，骨化程度较低(无尾类尤为明显)，颌弓与脑颅为自接式连接(腭方软骨直接与脑颅连接)。 d.典型五趾型四肢的出现。四肢位于躯干侧面，其骨骼中多有愈合现象，由乌喙骨.肩胛骨，上乌喙骨，锁骨组成的肩带不在与头骨愈合。从而使前肢的多样性活动有了可能，由髂骨，坐骨，耻骨组成的腰带与股骨形成髋关节，并与脊柱的荐椎相关节以支撑体重。 八(参考文献 《基础生命科学实验指导》 王洪钟主编 清华大学出版社 《动物学实验教程》 孙虎山主编 科学出版社 《普通动物学实验指导》 刘凌云、郑光美主编 高等教育出版社 《陈阅增普通生物学》 吴相钰等主编 高等教育出版社 《脊椎动物比较解剖学实验指导》 马克勤主编 高等教育出版社 coupling Centre shall be checked, the second poured concrete strength of more than 70%. In the process of reaming or boring, apart from the special provisions in factory, does not allow any work that may affect the coupling Centre, such as irrigation, to cylinder connections to flood the condenser pipes and so on. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Mounting bolts should be added lubricants, typing gently with a small hammer, not too loose or too tight, packed the bolts with the corresponding seal screw hole should be marked. 6.4.5.4.2 coupling reamed and pairings is close to the diameter of bolt bearing good hinge holes, dressed with a good two coupling bolts before you can move the rotor, boring-reaming hole in turn. Coupling bolts must be tight coupling is symmetrical diameter, in boring, reaming, two bolts out. Well boring, hinge bolt hole flange with coupling of vertical, not oblique. Due to the coupling bolts in accordance with hinge holes corresponding to the diameter of the screw holes one by one after processing, processing back bolt installation location cannot be changed, so according to bolt after the actual weight difference of nut and lock washer to match. General requirements for coupling two symmetrical diameter bolt, nut and lock washer's total weight difference should not be greater than 10 g and knocks stamped mark. (See Figure 18) The coupling bolts apply lubricant, and then gently with copper home, not too loose or too tight. Bolt Assembly is finished, symmetrical tightening all bolts to 30%, 50%, 70%, 100% force, and check the coupling flutter and before connecting the circle gradually changes its value should be less than 0.02mm. Tightening torque of the coupling bolts shall comply with the technical requirements manufacturers drawings, with a dynamometric wrench or log tension tools. Three wheel rotor swing test coupling connections should be checked: taking leave,