The Chord Conductance Equation gKE Na K Ee Where ∑g=k+吕M+ga Em membrane potential equilibrium potentials of the ion s conductance of the membrane to the ion s the more permeable, the greater the conductance
The Chord Conductance Equation Cl Cl Na Na K K m E g g E g g E g g E + + = where Em membrane potential Es equilibrium potentials of the ion s gs conductance of the membrane to the ion s. the more permeable, the greater the conductance. g = gK + gNa + gCl
All the ions that the membrane is permeable to contribute to the establishment of the potential of the membrane at rest °细胞膜在静息状态下对K的通透性一般大于其 它离子(主要是x),因此大多数细胞的静息膜 电位都是胞内为负 The Nat k+-ATPase contributes directly to generation of the resting membrane potential
• The Na+ ,K+ -ATPase contributes directly to generation of the resting membrane potential. • All the ions that the membrane is permeable to contribute to the establishment of the potential of the membrane at rest. • 细胞膜在静息状态下对K +的通透性一般大于其 它离子（主要是IK1），因此大多数细胞的静息膜 电位都是胞内为负
3. SUBTHRESHOLD RESPONSES 2 ms 膜电流V 刺激电流/ 刺激电流 A B 60 > 膜电流三 B 80 图2-1研究细胞膜电学性质的实验
3. SUBTHRESHOLD RESPONSES
graded potential The size(amplitude) of the subthreshold potential is directly proportional to the strength of the triggering event. A subthreshold potential can be either hyperpolarizing(make membrane potential more negative)or depolarizing(make membrane potential more positive)
• The size (amplitude) of the subthreshold potential is directly proportional to the strength of the triggering event. • A subthreshold potential can be either hyperpolarizing (make membrane potential more negative) or depolarizing (make membrane potential more positive) ➢ graded potential
注射电流 记录电极A 记录电极B 神经纤维 注射电流 记录电极A 动作电位 膜电位0 局部电位 m]-50