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18 Cards in this Set
- Front
- Back
Neuron
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a specialized cell that conducts impulses through the nervous system and contains three major parts--cell body, dendrites, and an axon.
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cell body
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the part of a neuron that contains the nucleus and carries out the metabolic functions of the neuron.
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Dendrites
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in a neuron, the branchlike extentions of the cell body that recieve signals from other neurons.
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Axon
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the slender, tail-like extention of the neuron that transmits signals to the dendrites or the cell body of other neurons and to muscles, glands, and other parts of the body.
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Glial cells
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specialized cells in the brain and spinal cord that hold neurons together, remove waste products such as dead neurons and preform other manufacturing, nourishing, and clean-up tasks.
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Synapse
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in the junction where the axon terminal of a sending neuron communicates with a recieving neuron across the synaptic cleft,
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Permability
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the capability of being penetrated of passed through
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Resting potential
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the slight negative electrical potential of the axon membrane of a neuron at rest, about 70 millivolts.
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action potential
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the sudden reversal of the resting potential, which initiates the firing of a neuron.
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Afferent neurons
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(sensory) relay massages from the sense organs and receptors --eyes, ears, nose, mouth and skin to the brain of spinal cord.
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Efferent Neurons
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convey signals from the central nervous system to the glands and the muscles, enabling the body to move
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Interneurons
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thousands of times more numorous than other two neurons, carry information btw neurons in th brain and btw neurons in the spinal cord.
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"all or none" law
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a neuron either fires completely or does not fire at all
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Refractory period
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immediately after the neuron is fired, during which it cannot fire again for 1 to 2 milliseconds.
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what is the neurological distinction btw feeling anxious about being disciplined by your boss for being late tp work nad running for your life to avoid being the victim of a criminal attacker?
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The answer lies in the number of neurons firing at the same time and their rate of firing. A strong stimulus may trigger thousands of neurons firing at the same time.
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Myelin Sheath
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the white, fatty coating wrapping around some axons that acts as insulation and enables impulses to travel much faster. The electrical impuse is retriggered/regenerated at each node (or naked gap) on the axon. (MS) involves deterioration of this fatty covering.
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Neurotransmitters
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a chemical substance that is released into the synaptic cleft from the axon terminal of a sending neuron, crosses a synapse, and binds to appropriate receptor sites on the dendrites of cell body od a recieving neuron, influencing the cell either to fire or not to fire.
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Receptors
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Protein molecules on the surface of dendrites and the cell bodies that will interact only with specific neurontransmitters. (puzzle peices)
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