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28 Cards in this Set
- Front
- Back
Neurons |
The basic signaling units, distinguished by their form, function, location and interconnectivity within the nervous system. |
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Soma |
The cell body of the neuron |
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Dendrites |
Are (usually) large treelike processes that receive inputs from other neurons at synapses. Postsynaptic. |
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Axon |
Transers information to other neurons. Presynaptic. |
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Saltatory conduction |
From the Latin ”saltare”, which means ”to jump”. The appearance of the action potential jumping along the myelinated axons from node to node. |
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Spines |
Little knobs attached by small necks to the surface of the dendrites; synapses are located on these spines. |
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Neurotransmitters |
The chemical substances that transmit the signal between neurons at chemical synapses. |
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Glial cell |
Also called neuroglial cell. A type of cell in the nervous system. |
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Blood-brain barrier (BBB) |
The astrocytic barrier between neuronal tissue and blood. Plays a vital role in protecting the central nervous system from blood-borne agents or compounds that might unduly affect neuronal activity. |
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Myelin |
A fatty substance that surrounds the axons of many neurons. |
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Nodes of Ranvier |
Nodes on an axon where important membrane specializations permit the generation of electrical signals, called action potentials, that are conducted down the axon. |
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Spike-triggering zone |
The region where long-distance signals, or action potentials, are generated, where spike refers to an action potential. |
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Resting membrane potential |
The difference in voltage across the neuronal membrane. |
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Ion channels |
Formed by transmembrane proteins that create pores, actual passageways across the membrane through which ions (charged atoms in solution) of sodium, potassium, and chloride (Na+, K+, and Cl-, respectively) might pass. |
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Permeability |
The extent to which a channel permits ions to cross the membrane. |
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Permeability |
The extent to which a channel permits ions to cross the membrane. |
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Electrical gradient |
The electrical potential that acts on an ion to drive the movement of the ion in one or another direction. That is, the environment outside becomes more positive than the environment inside the neuron. |
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Equilibrium potential |
EK = 59.8 log10 (20/400) = -75 mV Nerve and muscle cells encode information through changes in their membrane potentials. |
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Receptor potentials, Synaptic potentials, Action potentials |
Electrical currents. |
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Electrotonic conduction |
The passive and decrease of a charge along a nerve. |
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Depolarizations |
A passive current which makes the inside of the cell more positive and more likely to generate an action potential. |
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Depolarizations |
A passive current which makes the inside of the cell more positive and more likely to generate an action potential. |
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Hyperpolarization |
A passive current which makes the inside of the cell less positive and less likely to generate an action potential. |
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Threshold |
The value of the membrane potential to which the axon must be depolarized to initiate an action potential. |
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Refractory period |
The result of membrane hyperpolarization following the depolarization and repolarization of the action potential leaves the neuron in a temporary state in which it is less able to generate an action potential. This refractory period occurs when the membrane potential is even farther from the threshold required for triggering an action potential. |
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Propagation |
The propagation of action potentials is a continual interplay between electrotonic (passive) and active currents. |
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Receptors |
Specialized ion channels that mediate signals at synapses. |
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Second messagers |
Such as Ca+, cyclic nucleotides including cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP), nitric oxide, and other substances.
Involved in indirectly coupled receptors. |