Term
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Definition
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Term
| area of the skin supplied by nerve fibers originating from a single dorsal nerve root |
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Definition
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Definition
| according to the spinal nerve which supplies them |
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Term
| why are the dermatomes of the limbs more complex than those of the trunk |
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Definition
| dermatomes being pulled out as the limb buds form and develop during embryological development |
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Term
| why do adjacent dermatomes overlap |
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Definition
| overlapping innervation by adjacent dorsal roots |
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Term
| in regards to dermatomes, if there is loss of afferent nerve function by one spinal nerve, what happens to sensation form the region? |
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Definition
| not lost, but a reduction in sensitivity |
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Term
| overlap of of dermatomes depends on what |
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Definition
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| what type of dermatome overlaps less? |
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Definition
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| injury to a single dorsal root is more easily identified by examining for what |
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Definition
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| a group of muscles innervated by a single spinal nerve |
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Definition
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| what all neurons and their processes bounded by |
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Definition
| continuous plasma membrane |
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Term
| what is the neuronal membrane formed by |
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Definition
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| carbohydrate chains are found on what side of the phospholipid bilayer membrane |
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Definition
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| carbohydrate chains that are associated with membrane proteins are called what |
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Definition
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Term
| which region of the bilayer faces outward, hydrophilic or hydrophobic |
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Definition
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Term
| which region of the bilayer membrane faces inward |
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Definition
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Term
| characteristic of the hydrophilic heads of the bilayer membrane |
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Definition
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| characteristic of the hydrophobic tails of the bilayer membrane |
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Definition
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Term
| What substances are prevented from diffusing across the bilayer membrane |
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Definition
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Term
| Many processes carried out by nerve cells are initiated as a result of reactions occurring within the plasma membrane, what are these processes mediated by |
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Definition
| integral/intrinsic proteins embedded in the lipid bilayer |
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Term
| how can integral proteins move within the membrane? |
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Definition
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Term
| what do peripheral proteins attach to |
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Definition
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Term
| peripheral proteins can attach to integral proteins |
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Definition
| within the extra- or intracellular surfaces of the membrane |
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Term
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Definition
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Term
| central pores that selectively allow specific ions to diffuse down their concentration gradients |
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Definition
| channel proteins/ionophores |
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Term
| in which directions can ions move in channel proteins |
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Definition
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| if channel proteins are open only temporarily, what are they called |
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Definition
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| intrincis protein that maintains appropriate concentrations of ions on either side of the membrane by moving against their concentration gradient |
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Definition
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Term
| what is necessary for pump proteins to do their job effecively |
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Definition
| expend considerable metabolic energy |
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Term
| proteins that facilitate the movement of lipid-insoluble nutritients such as glucose into neuronal cytoplasm |
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Definition
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Term
| proteins that provide high affinity binding sites for specific molecules present in the extracellular fluid |
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Definition
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| molecules that bind to receptor proteins |
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Definition
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Term
| following the interaction of a receptor protein with a ligand, what may be present to couple the receptor to enzymes within the neuron |
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Definition
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Term
| following the interaction of a receptor protein with a ligand, transducer proteins may be present to do what |
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Definition
| couple the receptor to enzymes within the neuron |
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Term
| plasma membrane proteins that perform neurotransmitter reuptake |
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Definition
| neurotransmitter transporter proteins |
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Term
| what type of proteins are neurotransmitter transporter proteins |
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Definition
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Term
| transport of certain neurotransmitters from the synaptic cleft back into the presynaptic axon terminal |
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Definition
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Term
| Plasma membrane proteins, have only one function. True/False? |
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Definition
| False. Capable of being, for example, both receptor and channel protein |
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Term
| Extracellular fluid is high in what ions |
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Definition
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Term
| intracellular fluid is high in what ions |
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Definition
| K+, negatively charged proteins |
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Term
| Transmembrane potential typically |
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Definition
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Term
| 3 factors involved in the establishment of the resting membrane potential |
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Definition
| chemical(concentration) gradients, electrical gradients, electrochemical gradients |
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Term
[K+,K+,K+,K+]|[K+,K+]
Which way will the K+ flow? . Why? |
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Definition
| R. Lower concentration on right, higher concentration on left. |
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Term
| movement of ions across the cell membrane is called what |
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Definition
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Term
| the amount of current is inversely proportional to the ________ that separates the charges |
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Definition
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Term
| If resistance is high, current is |
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Definition
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Term
| If resistance is low, current is |
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Definition
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Term
| how can resistance in a cell membrane be changed |
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Definition
| opening/closing ion channels |
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Term
| sum of the chemical and electrical forces acting across the membrane |
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Definition
| electrochemical gradient for a specific ion |
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Term
| at rest Na+ ions are attracted into the cytosol, by the (-) charges on the inside of the cell membrane, resulting in which forces pushing Na+ into the cell |
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Definition
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Term
| what force tries to drive the K+ ions out of the cell |
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Definition
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Term
| what 2 electrical forces keep the K+ within the cell? |
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Definition
| attraction between the K+ and the (-) charges on the inside of the cell membrane, repulsion between K+ and (+) charges on outside of membrane |
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Term
| what are the 3 states of gated channels |
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Definition
| closed but capable of opening, open (activated), closed and incapable of opening (inactivated) |
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Term
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Definition
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Term
| what are the 2 classes of gated channels |
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Definition
| chemically regulated, voltage regulated |
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Term
| what class of gated channel is most abundant on dendrites and cell body |
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Definition
| chemically regulated channels |
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Term
| why are chemically regulated channels most abundant at dendrites and cell body |
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Definition
| areas where most synapses occur |
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Term
| voltage regulated channels open/close in response to what |
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Definition
| changes in transmembrane potentional |
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Term
| in regards to voltage regulated channels, what is the key step in the generation of an action potential |
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Definition
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Term
| what are the 2 gates the voltage regulated channel possesses? |
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Definition
| activation gate, inactivation gate |
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Term
| changes in the transmembrane potential that do not spread far from the area surrounding the site of stimulation are called what |
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Definition
| graded (local) potentials |
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Term
| in regards to graded(local) potentials, movement of Na+ across the membrane at one location causes what |
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Definition
| depolarization of the surrounding membrane |
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Term
| in regards to graded (local) potentials, teh change in the transmembrane potential and the area that is depolarized is directly related to what |
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Definition
| number of Na+ channels opened |
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Term
| in regards to graded (local) potentials, the more open channels, the more Na+ that enters resulting in what |
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Definition
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Term
| in regards to graded (local potentials) opening of K+ channels would result in what, |
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Definition
| K+ outflow rate would increase and the interior of the cell would become more negative |
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Term
| in regards to graded (local potentials) opening of K+ channels would result in K+ outflow rate would increase and the interior of the cell would become more negative. Which would result in what? |
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Definition
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Term
| Both depolarization and hyperpolarizaiton move the transmembrane potential away from.... |
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Definition
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Term
| What must occur for the transmembrane potential to return to resting levels |
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Definition
| removal of stimulus, restoration of normal membrane permeability |
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Term
| graded (local) potentials: transmembrane potential is most affected where |
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Definition
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Term
| graded (local) potentials: transmembrane potential is most affected at site of stimulation, meaning what |
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Definition
| effect decreases with distance |
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Term
| graded (local potentials): transmembrane poteital is most affected at site of stimulation, how does the effect spread |
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Definition
| passively due to local currents |
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Term
| graded (local) potential change may involved what |
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Definition
| depolarization or hyperpolarization |
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Term
| graded (local) potential: the stronger the stimulus, the greater the change in the transmembrane, therefore |
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Definition
| the larger the area affected |
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Term
| before an action potential can begin, what must occur |
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Definition
| an area of excitable membrane must be depolarized to threshold by local currents |
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Term
| Action Potential generation: what happens as a result of an area of excitable membrane being depolarized to threshold |
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Definition
| activation of Na+ channels followed by rapid depolarization |
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Term
| action potential generation: as the Na+ channels are activated and rapid depolarization occur the cell membrane becomes more permeable to what |
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Definition
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Term
| action potential generation: during activation of Na+ channels, the cell membrane is more permeable to Na+, causing what to happen to the transmembrane potential |
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Definition
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Term
| as the membrane reaches its target threshold (ex 30 mV) what happens to the Na+ gates |
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Definition
| gates are inactivated and become closed |
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Term
| as the membrane potential reaches its threshold (ex 30 mV) inactivation gates of the Na+ channels are closed due to what? |
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Definition
| inactivation gates of voltage regulated Na+ channels close |
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Term
| as the inactivation gates of voltage regulated Na+ channels close, what occurs at the same tiem |
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Definition
| voltage regulated K+ channels open |
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Term
| When the inactivation gates of voltage regulated Na+ channels close, and voltage regulated K+ channels open, what happens to the membrane potential |
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Definition
| shifts back toward resting, repolarization begins |
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Term
| at a potential of +30 mV, K+ ion movement is to the outside of the cell. Why? |
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Definition
| electrical and chemical gradients favor K+ ion movement |
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Term
| voltage regulated Na+ channels remain inactivated until the membrane potential reaches what |
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Definition
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Term
| Describe the state of voltage regulated Na+ channels when the membrane potential reaches -60 mV |
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Definition
| closed, but capable of opening |
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Term
| what happens to the K+ channels as the membrane reaches normal resting potential of -70 mV |
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Definition
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Term
| Why is the closing of K+ channels delayed briefly |
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Definition
| allows more than normal K+ ion to leave |
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Term
| What happens as a result of K+ ions taking more time to leave, in terms of polarization? |
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Definition
| transmembrane becomes more hyperpolarized, becoming even more negative than normal |
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Term
| from the time an AP begins until the normal resting potential has stabilized is called |
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Definition
| Absolute refractory period |
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Term
| why can the membrane not respond during the absolute refractory period |
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Definition
| all voltage regulated Na+ channels are either already open or are inactivated |
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Term
| period when the transmembrane is between -60 mV and -70 mV |
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Definition
| relative refractory period |
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Term
| the transmembrane will not respond to additional depolarizing stimuli during this period |
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Definition
| absolute refractory period |
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Term
| during the relative refractory period, why must the depolarizing stimulus be larger than normal electrically? |
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Definition
| membrane is hyperpolarized to some degree during the period |
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Term
| during the relative refractory period, why must the depolarizing stimulus be larger than normal chemically |
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Definition
| local current must deliver enough Na+ to counteract the loss of positively charged K+ through voltage regulated K+ channels |
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Term
| difference between action potentials and graded potentials |
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Definition
| APs affect the entire excitable membrane |
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Term
| when the AP reaches the end of the axon it is identical to the one generated at the initial segment, this is known as what |
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Definition
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Term
| Propagation of an AP in myelinated axons is referred to as what |
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Definition
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Term
| AP propagation: action potential begins at the initial segment, at the peak of the AP, the membrane potential becomes what |
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Definition
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Term
| AP propagation: After the peak of the AP, the membrane potential becomes (+), developing a local current that does what |
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Definition
| spreads in all directions |
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Term
| AP propagation: when the local current develops and spreads in all directions, what occurs |
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Definition
| depolarization of adjacent portions of the membrane |
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Term
| AP propagation: When the initial semgent of the axon is depolarized to threshold, what occurs |
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Definition
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Term
| AP propagation: When the initial segment of the axon is depolarized to threshold, an AP develops there, what happens next |
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Definition
| process continues in a chain reaction |
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