Term
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Definition
| a difference in electrical charge on the two sides of the membrane |
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Term
| Resting membrane potential |
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Definition
| a state where there is no net flow of ions across the membrane |
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Term
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Definition
| a change in the membrane potential to a less negative value inside. |
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Term
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Definition
| a wave of electrical excitation along a neuron's plasma membrane |
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Term
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Definition
| signal molecules that bind to their receptors at a synapse |
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Term
| Neurotransmitter receptors |
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Definition
| ligand-gated ion channels at a synapse |
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Term
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Definition
| caused by entry of positively charged ions into a neuron |
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Term
| voltage-gated sodium channels |
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Definition
| when opened allow more sodium ions to enter the cell down their electrochemical gradient |
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Term
| voltage-gated sodium channels |
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Definition
| open when membrane is sufficiently depolarised |
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Term
| voltage-gated potassium channels |
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Definition
| open to restore the resting membrane potential |
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Term
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Definition
| restores the sodium and potassium ions back to resting potential levels |
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Term
| vesicles containing neurotransmitter to fuse with the membrane / release of neurotransmitter into the synapse |
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Definition
| event when the action potential reaches the end of the neuron |
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Term
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Definition
| the tissue at the back of the eye which converts light into electrical signals |
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Term
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Definition
| cells that are sensitive to changes in light intensity and are particularly useful for vision in areas of low light intensity |
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Term
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Definition
| cells that are sensitive to specific colours (wavelengths) of light |
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Term
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Definition
| light-absorbing molecule in rod cells of retina |
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Term
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Definition
| membrane protein on rod cells that binds to retinal |
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Term
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Definition
| visual pigment formed when opsin and retinal combine |
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Term
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Definition
| formed when retinal absorbs a photon of light |
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Term
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Definition
| G-protein that is activated by photoexcited rhodopsin |
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Term
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Definition
| number of transducin proteins activated by single photoexcited rhodopsin |
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Term
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Definition
| enzyme activated by transducin |
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Term
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Definition
| number of phosphodiesterase enzymes activated by single transducin |
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Term
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Definition
| catalyses the hydrolysis of a molecule of cyclic AMP (cAMP) |
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Term
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Definition
| number of cAMPs broken down by one phosphodiesterase (PDE) |
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Term
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Definition
| effect of reduction in cGMP concentration |
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Term
| increase in membrane potential / triggers nerve impulses |
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Definition
| effect of closing the ions channels in neurons in the retina |
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Term
| high degree of amplification of signal (1>100s>1>1000s) |
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Definition
| what causes rod cells to be able to respond to low intensities of light. |
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