萝卜家园Chapter2ExcitationandConductioofnervous.ppt
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1、Chapter 2 Excitation and Conductio of nervous 神经的兴奋与传导,Metabolism 新陈代谢 Reproduction 生殖 Excitability 兴奋性,Nervous tissue : nerve cells (neuron,神经元) functional cells(功能细胞) neuroglia cells(神经胶质细胞). Support, nutrition, protection and isolation(绝缘).,NF (nerve fiber): long tubercle of neuron axon and long
2、dendrite. N (neuron): NF + connective tissue(结缔组织) Fig 2-2,Section1 Irritability and Excitability 应激性与兴奋性,1. Irritability应激性 Def : It is a kind of capacity that the vivo tissue and cells generate reaction for stimulus. 活的机体、组织、细胞对刺激 发生反应的能力 Example: amoeba(变形虫), sensitive plant(含羞草), tendential of p
3、lant(植物的向性)and silk tree(合欢).,condition: (1) sensibility for stimulus (2) signal conductibility (3) reaction of effecter Excitable cell: sensitive cell, nerve cell, muscle cell Excitability: irritability of excitable cells,2. Excitability兴奋性,excitation兴奋: Reaction of vivo tissue and cell for stimulu
4、s活组织或细胞对刺激发生的反应 transform变迁 Stimulated cells generate action potential细胞受刺激时产生动作电位,Excitability : a kind of capacity that vivo tissue and cell generate reaction for stimulus.活组织或细胞对刺激发生反应的能力 transform(变迁) a kind of capacity that cell generate AP for stimulus细胞受刺激时产生动作电位的能力,transform(变迁) a kind of pe
5、culiarity that cellular membrane conductance is changed for stimulus 细胞受刺激时膜电导产生改变的特性,Example : the sample of Sciatic nerve-gastrocnemius muscle (坐骨N-腓肠肌标本),Section 2 stimulation of causing excitation 引起兴奋的刺激,1. Def : It is a kind of change of internal and external environment which can cause cell e
6、xcitation 能引起细胞兴奋的内外环境条件的变化,2.Quality and Classification性质与种类 Quality: mechanical stimulus, chemical stimulus, temperature stimulus, electrical stimulus ect. electrical stimulus: the electrical stimulus of rectanglar waves(矩形波电刺激), controllable strength-duration(强度与时间可控), little damage 3. Essential
7、factors of stimulus刺激的要素 (1). intensity强度:,Threshold intensity(阈强度):When stimulus duration and rate of change is stable, tissue can generate excitation by a minimal intensity of stimulus, the minimal intensity of stimulus is called threshold intensity .刺激持续时间和 强度-时间变化率固定时,引起组织兴奋所需的最小刺激强度。 Threshold
8、stimulus(阈 刺 激): It is a kind of stimulus that intensity is equal to threshold intensity. Subthreshold stimulus(阈下刺激): It is a kind of stimulus that intensity is less than threshold intensity.,Supraliminal stimulus(阈上刺激): It is a kind of stimulus that intensity is more than threshold intensity. Maxi
9、mal intensity(顶强度): It is the minimal intensity of stimulus which can cause muscle to do the most contraction reaction.引起肌肉做最大收缩反应的最小刺激强度。 All or none(全或无): For single cell, once threshold intensity is reached, the cell will generate the maximal reaction. 对单个细胞来说,一旦刺激强度达到阈值,就会引起这个细胞作最大反应。,(2)Duratio
10、n The strength-duration curve of excited tissue 强度-时间曲线 Fig 2-6 Rheobase(基强度): the minimal threshold intensity. 最小的阈强度 Effective time(效用时间): (utilization time利用时). It is the shortest stimulative time which can excite tissue by stimulus of rheobase. 用基强度刺激,引起兴奋所需要的最短刺激时间,(3). Rate of change(强度的变化率) F
11、ig 2-7,Section 3 Index and Variation of excitability 兴奋性的指标和兴奋性的变化,1.Index of excitability兴奋性的指标 (1). Rheobase and threshold intensity 基强度与阈强度,excitability1/rheobase or threshold intensity For example: A muscle B muscle threshold 0.7V 1.2V excitability stronger weaker,2. Chronaxie时值 Def : When the i
12、ntensity of stimulus is twice as rheobase, the shortest duration of stimulus ,which can excite tissue, is called chronaxie.当刺激强度为基强度的二倍时,引起兴奋所需的最短刺激作用时间,excitability1/ chronaxie,3. changes of excitability during action potential and resumption (组织兴奋及其恢复过程中兴奋性的变化),phases excitability response Absolut
13、e refractory zero no response period绝对不应期 Relative refractory lower than response for period相对不应期 normal supraliminal stimulus Superanormal a little higher response for period超常期 than normal subthreshold stimulus Subnormal a little lower response for period低常期 than normal supraliminal stimulus,1. Di
14、scovery of bioelectricity生物电的发现 电鳗numbfish 伽发利Galvani (17371798) 动物电 animal electricity 伏特volt 双金属电流 A current by two kind of metals Fig2-13,Section 4 Bioelectricity phenomena 生物电现象,2. Resting potential and action potential 静息电位与动作电位 (1) Injury potential损伤电位 Def : The potential difference between in
15、jury site and intact site of tissue. 组织的损伤部位与完整部位之间的电位差 Essence: the potential difference of two sides of membrane. 膜两侧的电位差,(2) Resting potential 静息电位 Def :The potential difference between two sides of resting cellular membrane. 静息状态下细胞膜两侧所存在的电位差 Measure: microelectrode(微电极) Extent: -50- -100mv Pola
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