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	Membrane potential - Wikipedia, the free encyclopedia
		Action potentials are transient spikes in membrane potential characterized by initiating membrane potential changes that start the transmembrane flow of charged solutes through voltage-gated ion channels which in turn results in new membrane potential changes that ultimately return the membrane potential to the value it had at the start of the spike.
		Graded potentials that depolarize the membrane, reducing the membrane potential below the resting potential are important as "triggering potentials" that can spread along the surface of neuronal cell bodies to axon initial segments and trigger action potentials.
		Graded potentials are distinct from action potentials in that graded potentials spread electric potential changes along cell membranes without activating the kind of constant magnitude propagating signal that is characteristic of the action potential.
	en.wikipedia.org /wiki/Transmembrane_potential (2748 words)

	Module 6
		The action potential was considered the important signal; graded potentials were merely discrete negative or positive signals which produced the action potential.
		Graded potentials are not the whole story; the postsynaptic neuron must use the inputs it receives for something.
		Action potentials are very rapid changes in the membrane potential which originate at the axon hillock of a neuron and travel down the axon to the terminal bouton, where they cause the release of neurotransmitters into the synaptic cleft.
	cogsci.ucsd.edu /~pineda/guide/module_06.html (2152 words)

	Chapter 4 (Site not responding. Last check: 2007-10-21)
		Differentiate between a graded potential and an action potential.
		Differentiate between the current flow seen in a graded potential and the current flow associated with an (AP).
		Driving force is a measure of the electrical force that tends to move a charged ion across a cell membrane.
	www.austin.cc.tx.us /secrest/chapter4.htm (662 words)

	Neurons and Action Potentials
		As sodium ions rush in during the depolarizing phase of the action potential a large concentration of sodium ions accumulates in that region of the axon.
		A potential at the end of an axon is the same size as one recorded at the begining of the axon.
		One explanation is that it is the membrane potential at which the current caused by the influx of sodium is equal to the the current caused by the efflux of potassium.
	www.fortunecity.com /greenfield/buzzard/387/actionpot.htm (2144 words)

	lec07
		They are called graded potentials because the amplitude of the signal is directly proportional to the triggering event.
		graded potentials travel through the neuron until they reach a region called the trigger zone (In: efferent neurons at axon hillock and initial segment of the axon; sensory neurons adjacent to receptor).
		For an action potential to be initiated the membrane potential in the trigger zone must reach a minimum value called the Threshold voltage.
	www.sfu.ca /~ablaber/lec07.htm (624 words)

	[No title] (Site not responding. Last check: 2007-10-21)
		Definition: A graded potential is one kind of movement of an electrical impulse along a nerve fiber.
		Structure: A graded potential is a wave of electrical excitation that corresponds to the size of the stimulus.
		Graded potentials get weaker as they travel along nerve fibers, while action potentials remain the same strength as they travel.
	k-2.stanford.edu /InfoFrames/NervSys.1.3.html (120 words)

	Chapter 12 - Peripheral Nerves
		The compound action potential is graded in nature, in striking contrast to the all-or-none response of single axons.
		Note that the compound action potentials are smaller and later in the patient than in the normal person, because of the slowing of conduction in some fibers and block of conduction in others.
		It is graded because axons of the nerve are of differing diameters, and their thresholds to externally applied current vary with diameter.
	www.unmc.edu /Physiology/Mann/mann12.html (2361 words)

	[No title]
		The membrane potential of a cell has a slight imbalance in electrical charge across the plasma membrane, that is, the cell is slightly negative on the inside and slightly positive on the outside.
		Equilibrium Potentials, the Na+/K+ pump and the RMP If we examine the equilibrium potential of the important ions Na+ and K+ it nicely illustrates how the differences in permeabilities of these ions contributes to the value of the RMP.
		Spontaneous change in membrane potential - may be caused by 'leaky' channels, etc. The spread of a graded potential is decremental - that is, it diminishes over distance.
	www.miramar.sdccd.cc.ca.us /faculty/mmcmahon/docs/physam/lecNeuro.doc (4276 words)

	[No title]
		This represents a potential energy, which is called the potential difference or membrane potential, the measure of this potential energy is called voltage and is expressed in volts or millivolts.
		This membrane potential is present in all cells, including neurons and muscle cells when they are at rest (are not firing action potentials), and is called the resting membrane potential, or simply resting potential.
		GRADED POTENTIALS Graded potentials are short-lived local changes in membrane potential due to: Changes in membrane permeability to any ion (and hence the flow and distribution of that ion across the membrane) or Anything that changes the concentration of ions on either side of the membrane.
	www.zoology.ubc.ca /~biomania/biol153/lecture/nerve.doc (3747 words)

	Information Transfer Rate of Nonspiking Afferent Neurons in the Crab -- DiCaprio 92 (1): 302 -- Journal of ...
		The resting membrane potential of these neuron ranges from –65 to –70 mV when the receptor is slack and is approximately –55 mV when the receptor is held at a length equivalent to the mid-position of the TC joint.
		The peak-to-peak amplitude of the membrane potential fluctuation
		The membrane potential was recorded close to the transduction region and the average signal and noise power determined from repeated presentations of a 3.2 s random stimulus.
	jn.physiology.org /cgi/content/full/92/1/302 (5987 words)

	[No title]
		When an action potential depolarises a node, the charge is strong enough to depolarise the next node, skipping all of the distance in between.
		Action potentials are either all-or-nothing and their size is the same (completely independant of the size of the stimulus that created it).
		As the name implies, the potential is different for different levels of stimulus and the signal also degrades as it passes along the dendrite.
	www.cyberpunks.org /freeside/mab_neuro.html (1042 words)

	Human Physiology (IPHY 3430), University of Colorado at Boulder (Site not responding. Last check: 2007-10-21)
		Initially, a slight depolarization of the membrane occurs (i.e., the potential moves from the resting potential of -70 mv towards 0 mv).
		Upon initiation of an "all-or-none" action potential at the hillock of the axon, the impulse passes along the entire length of the axon at full strength.
		The action potential is initiated at the trigger zone and leaps down the axon one node at a time.
	www.colorado.edu /epob/epob1220lynch/04neuron.html (2260 words)

	Kretzberg et al 2001b
		Spikes can be superior to graded membrane potential fluctuations if spikes sharpen the temporal structure of neuronal responses by amplifying fast transients of the membrane potential.
		Such fast membrane potential changes can be induced deterministically by the stimulus or can be due to membrane potential noise that is influenced in its statistical properties by the stimulus.
		The graded response mode is superior for discrimination between stimuli on a fine time scale.
	www.uni-oldenburg.de /sinnesphysiologie/12429.html (183 words)

	Membrane Excitation -nerves, muscle, heart, etc
		Potentials are determined using sharpened glass micropipettes to puncture the cell.
		4) Amplitude of graded potential is directly proportional to the intensity of stimulus: Increase intensity - increase Na entering the cell - increase GP amplitude.
		is precisely halfway between the equilibrium potential for sodium and the equilibrium potential for potassium.
	www.elon.edu /shouse/physiology/physiol13/Lecture4.html (1085 words)

	The Performance of Synapses That Convey Discrete Graded Potentials in an Insect Visual Pathway -- Simmons 19 (23): ...
		potential and the amplitude of the spike (Fig.
		Burrows M, Siegler MVS (1978) Graded synaptic transmission between local interneurones and motoneurones in the metathoracic ganglion of the locust.
		Wilson M (1978b) Generation of graded potential signals in the second order cells of locust ocellus.
	www.jneurosci.org /cgi/content/full/19/23/10584 (7438 words)

	[No title]
		Na+ or K+ ______ Therefore, ______ is the major ion contributing to resting cell membrane potential.
		a) summation of A and X would reach threshold b) summation of C and A would be a graded potential c) summation of B and C would be a graded potential d) stimulation by A would depolarize cell e) repeated stimulation by B would temporally summate into a subthreshold depolarization 2.
		Action Potentials Are Conducted from the Trigger Zone to the Axon Terminal Conduction ensures that electrical energy is replenished so that the electrical signal does not lose _____________ over distance like _____________ potentials.
	www.miramar.sdccd.cc.ca.us /faculty/mmcmahon/docs/physam/NeuroQs.doc (750 words)

	Nervous System control (Site not responding. Last check: 2007-10-21)
		Graded potentials may be positive or negative and are proportional to the amount of stimulus received by the neuron.
		Many stimuli are typically required to produce a graded potential large enough to reach threshold.
		Usually, a single action potential in one neuron will not elicit an action potential in the neuron that it connects to.
	shakti.trincoll.edu /~odonnell/153/LectureStuff/nervous.html (416 words)

	Active Membrane Properties and Signal Encoding in Graded Potential Neurons -- Haag and Borst 18 (19): 7972 -- Journal ...
		the membrane potential of a motion-sensitive interneuron in the
		The root mean square error for the membrane potential was 86.2 ± 1.1°/sec and 91.5 ± 1.2°/sec for the spike train.
		The coherence calculated from the membrane potential was much higher than the one from the spike train.
	www.jneurosci.org /cgi/content/full/18/19/7972 (6828 words)

	Nerve Impulse
		potential (or potential difference) is the difference in charge between two points
		graded potentials are named based on where they occur and the function they perform
		depolarizing phase : increase in Na+ permeability and reversal of the membrane potential -- when the axonal membrane is depolarized by the graded potentials spreading from the soma and/or dendrites, voltage-dependent Na+ channels open, and Na+ rushes into the cell.
	www.xecu.net /kiirenza/anatomy/nerve1.htm (930 words)

	NS Lecture 15: Action Potential (Site not responding. Last check: 2007-10-21)
		Describe the changes in membrane potential (resting or action) of a nerve cell expected to occur as a consequence of changing either the chemical gradients for, or membrane permeability to, Na, K, or Cl. Discuss the relevance of such changes to the events that actually occur during a normal action potential.
		This is because of the capacitance of the membrane (we'll return to membrane capacitance during a discussion of the propagation of the action potential).
		When the potential reaches a particular level of depolarization, there is a rapid further depolarization during which the potential reaches and passes through zero and achieves a positive potential of approximately +57 mV!
	human.physiol.arizona.edu /SCHED/CV/Wright/15action.htm (1995 words)

	Neuron Action Potential
		All or None Principle - if the graded potential causes a threshold level depolarization, action potentials will be generated in the neuron.
		Graded potential that reaches threshold causes many voltage-gated Na channels to open (in addition to Na leakage channels) and voltage-gated K
		In adjacent axon area the graded depolarization causes voltage-gated Na channels to open and Na+ diffuses in.
	www.mtsu.edu /~jshardo/bly2010/nervous/actpot_nonav.html (442 words)

	Lecture Notes, February 2-7, 2000 (Site not responding. Last check: 2007-10-21)
		The action potential is all or none, the duration and amplitude (overshoot) are invariant, they cannot be summed.
		When an action potential is propagated to the synaptic terminal, depolarization of the terminal membrane (presynaptic membrane) opens voltage-dependent Ca channels increasing intracellular Ca The increase of Ca stimulates exocytosis of neurotransmitter that diffuses across the synaptic cleft to the postsynaptic membrane.
		The generator potential is a graded potential (like an EPSP) whose duration and magnitude is dependent on the strength and duration of the stimulus.
	www.spelman.edu /~biology/physiology/lectures/2_9.html (1188 words)

	[No title] (Site not responding. Last check: 2007-10-21)
		The resting membrane potential is often near the potassium equilibrium potential because: A.
		For an action potential to propagate in a nerve, the nerve membrane nearby an area that is firing an action potential must: A.
		The sodium channels are essential for action potentials in nerves Myelinated have a greater conduction velocity than unmyelinated fibers because: A.
	physio1.utmem.edu /~thomason/quizzes (794 words)

	Physiological Psychology, 7. Action Potential (Site not responding. Last check: 2007-10-21)
		Describe the ways that the resting potential may be altered.
		Explain how the graded potential allows the neuron to function as a decision maker.
		The action potential results because the Na+ permeability of the membrane is changed allowing Na+ to rush into the cell.
	neuro.psyc.memphis.edu /ugp/css007.html (452 words)

	HANDOUTS
		Does a single action potential spread to the end of the axon, or is it more accurate to say that each patch of membrane generates a new, identical, action potential?
		As this signal spreads, why isn’t it regenerated (boosted), like an action potential is? Does a single graded potential spread to the end of the axon, or is it more accurate to say that each patch of membrane generates a new, identical, graded potential?
		In terms of potential, what is different in about a neuron when it is generating a signal compared to when it is in a non-signaling state?
	www.utm.edu /staff/amills/handouts.htm (839 words)

	[No title]
		Graded potentials reaching threshold @ trigger zone initiate AP II.
		Threshold not reached, graded potential dies out, no AP produced III.
		Action Potential identical to one another don’t diminish as move down axon all or none principal frequency of AP’s reflects stimulus intensity as opposed to graded where size reflects stimulus intensity Action Potential 3 phases: rising, falling, after-hyperpolarization 1.
	www.angelo.edu /faculty/estraka/Actionpot.doc (241 words)

	[No title]
		The more stimulus, the more channels open, and the bigger the graded potential.
		Graded response (generator potential) triggers AP in same cell (if stimulus.over threshold) --> input to CNS.
		Graded response (receptor potential) triggers release/inhibition of transmitter by receptor cell -- amount of transmitter released proportional to stimulus.
	www.columbia.edu /cu/biology/courses/c2006/lectures/lect20.04.html (1397 words)

	Physiological psychology laboratory: potentials
		What will happen to the rate of rise of the action potential, to the threshold potential, to the peak of the action potential, to action potential duration, or to the duration of the refractory period?
		To find the amplitude of the graded potential, place the crosshairs cursor at the peak of the potential and read off the voltage in the measure window; then place the crosshairs at the resting potential level, and find the difference.
		The graded potential can take on any value, depending on the stimulus strength.
	www.ic.ucsc.edu /~bruceb/psyc123/potentials.html (876 words)

	A.S. French Publications
		French, A.S. (1984) Action potential adaptation in the femoral tactile spine of the cockroach, Periplaneta americana.
		French, A.S. (1984) The receptor potential and adaptation in the cockroach tactile spine.
		French, A.S. (1985) The effects of temperature on the action potential encoder of an insect mechanosensory neuron.
	asf-pht.medicine.dal.ca /ASF_Pubs/ASF_Pubs.html (5953 words)

	[No title]
		graded response in receptor cell is called a generator potential or receptor potential.
		Graded (generator) potential* triggers AP in same cell (if stimulus is over threshold) --> input to CNS.
		Graded (receptor) potential* triggers release/inhibition of transmitter by receptor cell -- amount of transmitter released is proportional to stimulus.
	www.columbia.edu /cu/biology/courses/c2006/lectures05/lect20.05.html (1557 words)

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