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24 Cards in this Set
- Front
- Back
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what is an action potential
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a sudden, transient, depolarizing deviation from the resting potential.
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what is the typical threshold potential in a neuron?
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–55 mV
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Can you increase the amplitude of the action potential once the threshold has been reached?
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An increase in the stimulus amplitude will not change the amplitude of the Action potential
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what are 3 purposes of the refractory period?
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a. Prevents back propagation of AP
b. Limits the maximum frequency of APs c. In the heart it reduces the chance for arrhythmias to occur  |
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Efferent neurons
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conduct action potentials down a motor nerve resulting in skeletal muscle contraction
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Afferent neurons
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created when peripheral receptors (touch, vision) convert analog information into digital form, to the central nervous system.
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what is the primary cause of action potentials in neurons ?
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synaptic transmission
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what are graded potentials?
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depolarizations or hyperpolarizations whose strength is proportional to the strength of the triggering event, they are not action potentials.
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what is the difference in amplitude and propagation of action potentials and graded potentials ?
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Action potentials have constant amplitude and rate, while graded potentials are proportional to input
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what do we call The wave of depolarization or hyperpolarization which moves through the cell with a graded potential ?
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local current flow.
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what causes the graded potential to loose strength as it passes through a cell?
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the leakage of charge across the membrane
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what is an excitatory postsynaptic potential (EPSP).
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A graded potential depolarization
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what are inhibitory postsynaptic potentials (IPSP).
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graded potential hyperpolarization
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what two factors determine if the action potential threshold is reached?
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stimulus strength and duration
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what is rheobase?
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The minimum current that can cause an action potential
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chronaxie
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the minimum stimulus time that will cause an AP
using a current twice the rheobase current |
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what is the M gate?
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Na+ gate on the extracellular side is called the activation gate
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what is the H gate?
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Na+gate on the intracellular side is called the inactivation gate
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which gate (m/n) has to be open for sodium to pass?
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BOTH
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what is the n gate?
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the ONLY potasium gate
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what is the amplitude of a typical action potential?
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+30
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does the action potential reach the sodium equilibrium potential for Na+?
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no
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what causes the "n" gate to open?
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depolarization
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which Ions are responsible for carrying current inside and outside of the cell ?
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K+ carries inside and Na+ carries outside
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