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Definition
| source of electrons; higher charge |
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Definition
| destination of electron flow; lower charge |
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Definition
| flow of electrons from body with higher charge (more electrons) to one with lower charge (fewer electrons) |
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Definition
| insulated wire or saltwater filled glass tube used for electrical stimulation/recording; conductor |
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Term
| What did Galvani find out about electricity/the body? |
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Definition
| stimulating a dissected nerve makes the muscle twitch, thus he though that electricity flows along the nerve |
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| What did Penfield find out about electricity/the body? |
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Definition
| mapped neocortex of humans through electrical stimulation |
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Definition
| measures differences in electrical potential btwn bodies |
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| What did von Helmholtz find out about electricity/the body? |
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Definition
| flow of info in nervous system is too slow to be electrical flow |
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Term
how does the giant axon of the squid help the squid?
how does it help scientists? |
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Definition
helps the squid b/c the larger diameter of the axon means faster messages which helps the squid propel away from predators;
it helps scientists b/c its easier to see and perform experiments on. |
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Term
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Definition
| measures flow of electrons |
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Definition
| small electrodes made with etching wire or by heating and pulling tubes of glass |
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Definition
| difference in substance concentration across regions causing movement via diffusion |
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Definition
| passive force that moves substances from area of higher to lower concentration through random motion |
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Definition
| difference in electrical charge across regions, causing movement due to electrostatic pressure |
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Definition
| passive force based on attraction of opposite-charge ions and repulsion of same-charge ions |
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Term
| T or F :ions can want to move in 2 directions at once given opposite concentration and voltage gradients |
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Definition
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Term
| How does a cell membrane store potential energy? |
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Definition
| It maintains gradients as source of potential energy , to release by opening channels at appropriate times |
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Term
| resting potential (definition and number) |
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Definition
voltage across membrane in absence of stimulation;
-70 mV |
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Term
| Na+-K+ pumps use energy to put _ (number) Na+ out for every _ (number) K+ taken in |
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Definition
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Term
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Definition
| small brief voltage fluctuations in area of cell membrane where ion concentration changes |
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Definition
| increase in membrane polarity (more negative inside, neuron less likely to fire) |
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Definition
| decrease in membrane polarity (less negative inside, more likely to fire) |
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Definition
| large, brief reversal in polarity of axon membrane (up to 30 mV) |
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Term
| action potential occurs when total depolarization bring membrane to _______ at __ mV |
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Definition
| threshold potential at -50 mV |
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Term
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Definition
| action potential has same strength regardless of strength of trigger; +30 mV at peak regardless |
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Term
| Strength of triggering stimulus can affect ______ (frequency/strength) of action potentials |
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Definition
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Term
| action potential phases (5 of them) |
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Definition
1) resting: before action potential; Na+ and K+ channels closed
2) depolarize: threshold potential reached; Na+ channels open, Na+ influx, polarity reversing
3) repolarize: Na+ channels close, K+ channels open, K+ outflux, polarity reversing
4) hyperpolarize: K+ channels still open, membrane even more polarized than at resting potential
5) back to resting phase using Na+-K+ pump necessary to restoring ion concentrations back to resting potential conditions |
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Term
| absolute refractory period--during which phases of action potential does this apply |
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Definition
| new action potential cannot be elicited during depolarize/repolarize phases |
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Term
| relative refractory period--during which phases of action potential does this apply? |
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Definition
| increased current required for another action potential; hyperpolarize phase |
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Term
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Definition
| propagation of action potential along axon membrane |
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Term
| what makes nerve impulses unidirectional? |
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Definition
| refractory periods prevent them from going back |
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Term
| T or F: action potentials dissipate over distances during nerve impulses |
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Definition
| F, b/c of constant size/all or none law |
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Term
| myelination is done by what kind of glial cells and does what to neural impulse? |
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Definition
| oligodendroglia in CNS and Schwann cells in PNS--speeds up neural impulse |
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Term
| is there action potential where there is myelin on an axon? why? |
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Definition
| no, b/c of insulating barrier against cross-membrane flow and there are few ion channels under myelin |
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Term
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Definition
| tiny gaps where axon is not covered by myelin and with a lot of voltage-gated channels |
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Term
| how does the action potential signal relate to nodes of ranvier? |
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Definition
| between nodes the ions flow faster, but weaken with distance and then at nodes they trigger new action potential to refresh the signal |
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Term
| How many connections can a neuron have with other neurons via dendritic spines |
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Definition
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Term
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Definition
| brief, tiny, local change sin membrane potential in response to stimulation (graded potential, but specific to postsynapic membrane) |
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Term
| ESPS-excitatory postsynaptic potentials |
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Definition
| depolarizing (via Na+ influx); action potential more likely |
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Term
| inhibitory postsynaptic potential IPSP |
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Definition
| hyperpolarizing (via K+ efflux/Cl- influx); action potential less likely |
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Term
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Definition
| graded potentials occurring at about same time on membrane are summated |
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Term
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Definition
| graded potentials occurring at aobut the same location are summated |
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Term
| axon hillock where is it and what happens here in terms of action potential and EPSP/IPSP? |
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Definition
| junction of cell body and axon; rich in voltage-gated channels; where EPSP and IPSPs are integrated; action potential starts here if net effect reacher threshold potential |
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Term
| sensory receptors have __________ (2 words) on membranes that can trigger action potentials, e.g. tactile stimulation |
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Definition
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Term
| where are stretch sensitive Na+ channels and what do they do? |
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Definition
| they are on dendrites wrapped around hair shafts and open when hair is displaced |
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Term
| What are axon terminals and where are they when related to motor movement? |
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Definition
| ending of axon that connects to neural target and contains neurotransmitters; axon terminals of motor neurons synapse on end plates of muscle cells |
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Term
| amyotrophic lateral sclerosis (ALS) |
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Definition
| motor neurons degenerate and person loses voluntary muscle control |
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Term
| action potential in muscle cell leads to _____ rather than nerve impulse |
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Definition
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Term
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Definition
| measuring action potentials in individuals cells with small insulated wire microelectrodes |
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Definition
| neuron in hippocampus that fires when animal faces in particular direction within an environment (codes for orientation) |
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Term
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Definition
| neuron in hippocampus that fires when animal is in particular location in an environment (codes for location, not orientation) |
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