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53 Cards in this Set
- Front
- Back
membrane potential
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the difference in electrical charge between teh inside and the outside of a cell
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microelectrodes
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intracellular electrodes less tan one thousandth of a millimeter in diameter
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the inside of neuron is how many millivolts
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-70
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resting potential
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;steady membrane potential o f about -70 mv
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teh neuron is polarized
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when its in its restin gstate, with teh -70 built up across its membrane.
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ions
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postively and negatively charged particles
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ions move down their____-
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concentration gradient
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electrostatic pressure
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any accumulation of charges, positve or negative in one area tends to be dispersed by the repulsion among the like charges in teh cinity adn teh attraction of oppostie charges concentrated elsewhere
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there are four kidns of ions what are they
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Na+, K+ chloride ions Cl- and variosu negatively charge protein ions A-
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random motion
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molecules move from areas o f high concentraion to low to distrubte evenly
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electrostatic forces
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like charges repel opposite chrages attract, to
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differentially permeable
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ions pass thru membrane at pores selective for each ion
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three different membrane potentials
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resting potential, post synaptic potentials, and graded post synaptic potentials
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post synaptic potentials have two
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EPSP excitatory and inhibitory post synatpic potentials
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EPSPS
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increase likelihood tha tneuron will fire and, depolarizations, becomes more POSTIIVE
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IPSP
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decrease likelihood neuron will fire, hyperpolarizations, and become more NEGATIVE
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axon hillock
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the ocnical structure at the junction between teh cell body adn teh axon
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threshold of excitataiton
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usually about -65 mv and action potential is generated near teh axon hillock.
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the action potential
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massive momentary lasting for one millisecond reversal lf te membrane potential from about -70 to 50 mv.
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all or none responses
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they eithe roccur to their full exten or do not occur at all
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graded responses
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this means that the IPSP AND EPSP are proportional to the intesnity of thes inals
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voltage activated ion channels
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ion channels that open or close in response to changes in the level of the membrane potential
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nondecremental
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action potentials do not grow weaker as they travel along teh axonal membrane.
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nodes of ranvier
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the gaps between adjacent myelin segments.
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saltatory conduction
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the transmission of action potentials in myelinated axons.
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peptides
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amino acid chains that are composed of 10 or fewer amino acids; in effect they are short proteins.
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synaptic vesicles
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small molecule neurotransmitters are typically synthesized in teh cytoplasm of the terminal button and packaged in these synaptic vesicles
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exocytosis
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the process of neurotransmitter release
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receptors
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each receptor is a protein that contains binding sites for only particular neurotransmitters; thus a neurotransmitter can influence only those cells that have receptors for it.
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ligand
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any molecule that binds to another
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ionotropic receptors
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receptors that are associated with ligand-activated ion channels
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metabotropic receptors
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receptors that are associated with signal proteins and G proteins
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second messenger
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a chemical synthesized in a neuron in response to the bindin of a neurotransmitter to a metabotropic receptor in its cell membrane.
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autoreceptors
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metabotropic receptors that have two unconventional characteristics.
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reuptake
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the drawin gback in to the terminal button of a neurotransmitter molecules after their release into the synapse; the more common of the tw mechanisms for deactivating a released neurotransmitter
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enzymatic degradation
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the breakdown of chemicals by enzymes- one of the two mechanisms for deactivating released neurotransmitters.
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enzymes
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proteins that stimulate or inhibit biochemicalreactions without being affected by them
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acetylcholine
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one of teh few neurotransmitters for which enzymatic degradation is the main mechanism of synaptic deacivation
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acetylcholinesterase
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breaks the Acetylcholine
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gap junction
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are narrow spaces between adjacent neurons that are bridged by fine tubular channels that contain cytoplasm.
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amino acids
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the molecular buildin blocks of proteins
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teh four most widely acknowledged amino acid neurotransmitters
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glutamate, aspartate, glycine, adn gamma aminobutyric acid (GABA)
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monoamines
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another class of small molecule neurotransmitters.
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four monamine neurotransmitters
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dopamine, epinephrine, norepinephrine, and serotonin.
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neuropeptides
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peptides that play a role in neurotransmission
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agonists
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drugs that facilitate teh effects of a particular neurotransmitter
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antagonists
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drugs that inhibit the effects of a particular neurotransmitter
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receptor blockers
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antagonistic drugs bind to postsynaptic receptors without activating them and, in so doing, block the access of the usual neurotransmitter
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cocaine
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is a potent catecholamine agonist that is highly addictive.
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atropine
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active ingredient of belladonna.
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curare
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an extract of a certain class of woody vines
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neuromuscular junctions
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the synapses of a motor neuron on a muscle
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botox
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a neurotoxin released by a bacterium often found in spoiled food. is a nicotinic antagonist.
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