第二章细胞的兴奋 chap. 2 The resting membrane potential chap 3 Action potential chap. 16 Electrical activity of the heart chap. 17 Natural excitation of the heart from Berne Levy Principles of Physiology (4thed)2005
• chap. 2 The resting membrane potential • chap. 3 Action potential 第二章 细胞的兴奋 from Berne & Levy Principles of Physiology (4th ed) 2005 • chap. 16 Electrical activity of the heart • chap. 17 Natural excitation of the heart
Observations of Membrane Potentials 1. IONIC EQUILIBRIA 2. RESTING MEMBRANE POTENTIALS 3. SUBTHRESHOLD RESPONSES 4 ACTION PONTIELS 5.心肌细胞和起搏细胞的动作电位
Observations of Membrane Potentials 4. ACTION PONTIELS 1. IONIC EQUILIBRIA 2. RESTING MEMBRANE POTENTIALS 3. SUBTHRESHOLD RESPONSES 5. 心肌细胞和起搏细胞的动作电位
>Observations of Membrane potentials Extracellular recording Oscilloscope ++++++++ 8■|0 50 90七 Time ++++++++十 (a) Nerve cell
➢Observations of Membrane Potentials • Extracellular recording
o Intracellular recording Oscilloscope ++++++++ 8■0 50 ooo Time +++++++++ (b) Nerve cell
• Intracellular recording
● Voltage clamp 膜电位 跟随放大器 电位 电极 轴突 指令电位 反馈放大器 电流电极 膜电流 图2-14电压钳原理示意图
• Voltage clamp
macroscopical current 膜电位 钾电流 (b) 膜电流 总电流 1 ms
macroscopical current
● Patch clamp 玻璃微吸管 反馈放大器电流 电极 指令电压 通道 细胞膜 图2-18膜片钳原理和钠通道活动
• Patch clamp
single channel current 去极化 M减牌啤一关闭 一开放 w4以M牌一关闭 开放 yw4wWA小一关闭 一开放 0.5pA 100ms 对照
single channel current
1. IONIC EQUILIBRIA Concentration force A I M 0.]M X+ +++++ X+
1. IONIC EQUILIBRIA Concentration force Electrical force
Electrochemical Equilibrium When the force caused by the concentration difference and the force caused by the electrical potential difference are equal and opposite, no net movement of the ion occurs, and the ion is said to be in electrochemical equilibrium across the membrane When an ion is in electrochemical equilibrium, the electrochemical potential difference is called as equilibrium potential or Nernst potential
Electrochemical Equilibrium • When the force caused by the concentration difference and the force caused by the electrical potential difference are equal and opposite, no net movement of the ion occurs, and the ion is said to be in electrochemical equilibrium across the membrane. • When an ion is in electrochemical equilibrium, the electrochemical potential difference is called as equilibrium potential or Nernst potential