Unit 3 Word Scramble
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| Question | Answer |
| The resting membrane potential is maintained by Na K pumps that actively transport ___ into and ____ out of the cell. | K Na |
| In RMP the concentration of ___ is higher inside than outside the cell. | K |
| In RMP the membrane is more permeable to ____. | K |
| In RMP the concentration of ___ is higher outside than inside the cell | Na |
| EPSPs and IPSPs summate at the _____ __________. | axon hillock |
| Most CNS neurons fall into which structural category? | Multipolar |
| Which cell produces myelin and is located in the PNS? | schwann cells |
| What cell produces myelin in the CNS? | oligodendrocytes |
| Demyelination disorders such as Multiple Sclerosis and Guillain-Barre Snydrome are particularly dangerous because they do what? | decrease the speed of action potential transmission |
| The sodium-potassium exchange pump stabilizes resting potential of the neuron membrane at about _____. | -70 mV |
| The most abundant intracellular cation is _________ while the most extracellular anion is _____________. | Potassium Chloride |
| Where do most action potentials originate? | Initial segment |
| What opens first in response to a threshold stimulus? | voltage gated Na channels |
| What characterizes depolarization, the first phase of the action potential? | the membrane potential changes from a negative value to a positive value |
| What characterizes depolarization, the second phase of the action potential? | Once the membrane depolarizes to a peak value of +30mV, it repolarizes to its negative resting value of -70mV |
| What event triggers the generation of an action potential? | The membrane potential must depolarize from the resting voltage of -70 30mV to a threshold value of -55mV |
| What is the first change to occur in response to a threshold stimulus? | Voltage-gated Na channels change shape, and their activation gates open. |
| What type of conduction takes place in unmyelinated axons? | continuous conduction |
| An action potential is self-regenerating because__________. | depolarizing currents established by the influx of Na flow down the axon and trigger an action potential at the next segment |
| Why does regeneration of the action potential occur in one direction, rather than in two directions? | The inactivation gates of voltage-gated Na channels close in the node, or segment, that had just fired as action potential. |
| What is the function of the myelin sheath? | The myelin sheath increases the speed of action potential conduction from the initial segment to the axon terminals. |
| What changes occur to voltage-gated Na and K channels at the peak of depolarization? | Inactivation gates of voltage-gated Na channels close, while activation gates of voltage-gated K channels open |
| In which type of axon will velocity of action potential conduction be the fastest? | Myelinated axons with the largest diameter |
| What is an example of a presynaptic cell? | a neuron |
| What separates the presynaptic and postsynaptic cells at a chemical synapse? | synaptic cleft |
| What role does calcium have in synaptic activity? | Calcium influx into the synaptic terminal causes vesicle fusion with the plasma membrane in the release of neurotransmitter. |
| What is the role of neurotransmitter at a chemical synapse? | Neurotransmitter binds to receptors on the postsynaptic cell membrane |
| What is the primary role of the enzyme AChE At a cholinergic synapse? | Ache degrades Ach in the synaptic cleft |
| If a nerve cell receives many IPSPs In different locations at the same time ____. | It will show spatial summation |
| The neurotransmitter GABA blocks presynaptic voltage-gated calcium channels. Consequently, GABA produces _______. |
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Beckster89