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17 Cards in this Set
- Front
- Back
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What is relationship between single channel current and actual membrane current?
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A single channel conductance x the open probability is equal to the Actual membrane current. If you multiply the actual current x the # of channels equal the macroscopic current.
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How many gates in the K+-delayed rectifier channel?
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1 gate
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What is the Probability of the K+ delayed rectifier channel being opened?
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P= n^4
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How many gates in the Na+ channel?
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2 gates
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What is the Probability of the Na+ channel being opened?
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P= m^3xh
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What states does the K+ delayed rectifier channel undergo before it becomes inactivted?
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it goes from C1--> C2 --> Open--> Inactive
C2=resting state C1= |
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What is special about the A-type K channels?
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they have a ball and chain mechanism that inactivates channel
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When is there no conductance of Na+ after sequential stimulation?
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During the Absolute Refractory period i.e since their is no Na+ conductance then their is no AP
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When is there partial conductance of Na+ after sequential stimulus?
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During the Relative Refractory Period: Last about 10 ms
i.e Na+ conductance slowly increases |
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What controls the Space response (i.e Slow Depolarization) prior to reaching AP treshold?
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Transient outward K+ channels
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What causes pacemaker activity?
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Ca++ dependant K-channels produce a slow after hyperpolirization causing a long resting period in where intracellular calcium prevent Vm from reaching AP threshold eventually Ca++ is lowered by Ca++-pumps which slowly repolarize
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What Shapes Action Potentials?
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Ca++dependant K-channels
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What causes a FAST After-hyperpolarization?
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voltage gated delayed rectifier K channels
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What causes a SLOW Afterhyperpolarization?
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Ca dependant K channels
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Where does Ca++ come in through?
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voltage gated Ca channels
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What is the equation for single channel current i.e ohms law single channels currents?
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i(open)= signal channel conductance x(Vm-Nerst potential)
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What is the macroscopic membrane current equation?
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i(open) x Open Probability x number of open channels
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