action potentials Flashcards
depolarization
potential becomes less negative
hyperpolarization
potential becomes more negative
voltage clamp method
measures the membrane potential with an electrode inside the cell and electronically compares this voltage to the maintained
- indicates how membrane potential influences ion current flow across the membrane
membrane conductance
the reciprocal of the membrane resistance
regenerative
a process that is self-sustaining
conduction velocity
the speed at which an action potential is propagated along an axon
- defines the time required for electrical info to travel from one end of a neuron to another
saltatory
mechanism of action potential propagation in myelinated axons
how many states do K+ channels have
two: open and closed
how many states do Na+ channels have
three: resting, activated, inactivated
two gates: activation gate and inactivation gate
resting - activation gate closed, inactivation gate open
activated - both gates open
inactivated - inactivation gate closed
postsynaptic potential (PSP)
the potential change produced in a postsynaptic neuron by the binding of neurotransmitter released from a presynaptic neuron
graded potential
small voltage fluctuations in the cell membrane
- initially restricted to the part of the membrane where ion concs changes to cause a brief change in electrical charge across the cell membrane
two types of PSPs
inhibitory postsynaptic potentials (IPSP)
excitatory postsynaptic potentials (EPSP)
IPSP
brief hyperpolarization of a neuron membrane in response to stimulation
- neuron is usually less likely to produce an action potential
- usually involve GABA mediated Cl- conductance
EPSP
brief depolarization of a neuron membrane in response to stimulation
- neuron is more likely to produce an action potential
