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17 Cards in this Set
- Front
- Back
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Which neuroglial cells are the macrophages of the CNS?
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microglia
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Which neuroglial cells produce myelin sheath insulation in the CNS?
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oligodendrocytes
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Which neuroglial cells support and help tissue of the CNS?
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astrocytes
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Which neuroglial cells produce cerebrospinal fluid?
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ependymal cells
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Which neuroglial cells produce myelin sheath insulation in the PNS?
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Schwann cells
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Which neuroglial cells support and help nervous tissue in the PNS?
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satellite cells
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Which neuroglial cells are found in the digestive system?
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enteric glia
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Whice ions are impermeable to membranes?
K+ Cl- Na+ Ca2+ |
Na+ and Ca2+
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If ion is negatively charged, increasing the concentration outside will make the energy potential...
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More negative
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If ion is positively charged, increasing the concentration outside will make the energy potential...
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More positive.
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Decreasing the concentration of calcium outside of the cell does what to the conductance of sodium?
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It increases the conductance of sodium.
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What is the approximate threshold for an action potential to occur?
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-55 mV
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Why does the membrane hyperpolarize past the resting membrane potential after depolarization?
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The potassium channels are slow to close and continue to allow the positive ions out.
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What is the cause of the absolute refractory period?
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The inactivation of the voltage-gated Na+ channel until the membrane potential repolarizes sufficiently enough to begin opening the inactivation gates.
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What is happening during the relative refractory period?
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Sodium channels are opening but slow-closing potassium gates increase the threshold for impulse initiation as a greater stimulus is required to depolarize the hyperpolarized membrane.
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Why will an action potential never reach the Na+ equilibrium potential?
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Because the voltage-gated Na+ channel inactivates almost immediately after opening.
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How does decreasing the resting membrane potential affect the initiations of an action potential?
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The membrane is depolarized. This may cause opening of sodium channels, but not to the point of initiating action potential. Eventually the open channels inactivate and become refractory, thus increasing the threshold to generate an action potential. This may cause paralysis.
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