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40 Cards in this Set
- Front
- Back
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Nerves
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Bundles of peripheral nerve fibers held together by several layers of connective tissues
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Endoneurium
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Surrounding each nerve fiber is a delicate layer of fibrous CT
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Perineurium
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Bundles of fiber called fasicles held together by CT
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Within the central nervous system bundles of nerves fibers are called
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Tracts
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Bundles of mylelinated fibers make-up the so-called
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White matter or white substance
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Cell bodies and unmylelinated fibers make up the darker
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Gray matter or gray substance
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In peripheral nerves, similar regions of gray matter are more often called
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Ganglia
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Mixed nerves contain
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Sensory -afferent and motor-efferent
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Name the step to repair peripheral nerve fiber
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??
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There is a slight excess of positive ions on the outside of the membrane and a slight excess of negative ions on th inside of the membrane. This results in a difference in electrical charges called
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Membrane Potential
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The magnitude of potential difference between 2 sides of polarized membrane is measured in
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Volts (V) or millivolts (mV)
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The membrane potential maintained by a nonconducting neuron's plasma membrane is called
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Resting membrane potential (RMP)
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Sodium Potassium Pump
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It moves 3 sodium ions out of a neuron for every 2 potassium ions it moves into it.
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Because more positive ions are pumped out than brought in what type of charge develops inside the cell?
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Negative charge
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A slight shift away from the RMP in a specific region of the plasma membrane is often called
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Local Potential
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Movement of the membrane potential toward zero is called
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Depolarization
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Movement of the membrane potential away from zero
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Hyperpolarization
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Because the magnitude of deviation from the RMP is proportional to the magnitude of the stimulus local potential are called
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Graded Potential
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The membrane potentail of an active neuron one that is conducting and impulse is called
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Action Potential
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Action Potential is often called
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Nerve impulse
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Name 5 steps in Action Potential
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??
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Depolarization occurs when
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Na+ channels open allowing Na+ to move in an area of lower concentration
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Repolarization occurs when
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K+ channels then open allowing K+ to move toa an area of lower concentratrion outside the cell
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Resting membrane Typi9cal Voltage
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-70 mV
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Threshold Potential Typical Voltage
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-59 mV
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Action Potentail Typical Voltage
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+30 mV
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Speed of nerve conduction depends on diameter and on the presense or absence of
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Myelin sheath
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Brief peroid lasting approx half a millisecond during whicdh a local area of a neurons membrane resist restimulation and will not respond to a stimulus no matter how strong
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Absolute Refractory Peroid
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Time during which the membrane is repolarized and is restoring the resting membrane potential: the few milliseconds after the absolute refractoru peroid membrane will respond to a very strong stimulus
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Relative Refractory Peroid
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Place where signals are transmitted from one neuron called the
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Presynaptic Neuron
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Two types of Synapses
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Electrial Synapses and chemical synapses
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Occur where cells joined by gap junctions allow an action potential to simply continue along the postsynaptic membrane and they are found in cardiac muscle and single-unit smooth muscle
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Electrical synapse
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Chemical transmitter called a neurotransmitter to send a signal from the presynaptic cell to the postsynaptic cell is called
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Chemical Synapse
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Tiny bulge at the end of a terminal brance pf a resynaptic neuron axon is called
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Synaptic Knob
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The space between a synaptic knob and the plasma membrane of a postsynaptic neuron is called
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Synaptic Cleft
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Postsynaptic can only be found
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Muscle, gland or another neuron
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Adding together the effects of several knobs being activated simultaneously and stimulating different locations on the postsynaptic membrane producing an action potential is what type of summation
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Spatial
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When synaptic knobs stimulate a postsymptic neuron in rapid succession their effects can summate over a brief period to produce an action potential
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Temporal Summation
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Function is determined by the postsynaptic receptors not the neurotransmitters themselves are called
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Neurotransmitters
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Neurotransmitters are known as
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Acetylcholine, Norepinephrine, Dopamine & Serotonin
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