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15 Cards in this Set
- Front
- Back
Mylinated Neurons
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Depolarization occurs at nodes of Ranvier. Cytoplasm of neuron conducts enough electrical charge to depolarize next node. thus impulse jumps from node to node in a process called salutatory conduction. Schwann cells allow ions to cross membrane only at nodes. |
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Non-mylinated neurons
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Travels as a wave along the whole length of the axon membrane. Slower than salutatory conduction
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Diameter of Axon
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Greater diameter, the greater the speed. Small diameter gives a large SA:Volume ratio which causes the amount of ions to leak out of the axon thus making it more difficult for action potential to propagate. |
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Temperature |
Higher temperature means a faster speed of impulse. Temperature affects the rate of diffusion of ions across the axon.
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After EPSP
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ATC is released from protein receptors, is the broken down by enzyme (Acetylechinease) to chlorine and CH3COOH. They then rapidly diffuse into pre-synaptic membrane and are incorporated into vesicles. ATP is released by mitochondria which combines both products to ATC.
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Two types of Synapses |
Cholinergic-Aceylchlorine NT Adrenergic- Adrenaline NT |
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Spatial Summation |
Different Neurons firing simultaneously at one neuron which adds together to surpass threshold.
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Temporal Summation
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Same neuron which is rapidly firing in a short amount of time to build up impulse to reach threshold
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Excitatory Neuron
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-Na and K ion channels open -Na enters faster than K -Depolarization occurs -reach's threshold - EPSP is formed |
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Inhibitory Synapse |
-K and Cl channels open -K exit and Cl enters -Membrane becomes more negative -Hyperpolarization of neuron - IPSP is formed |
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Amphetamines |
Force a neutral mutter called dopamine out of synaptic vesicles and into the synaptic clefts. This increases effect of dopamine.
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Opioids |
Block calcium ion channels in the presynaptic membrane so less NT released. |
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Nerve gases |
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Curare |
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Nicotine |
Minimics acetylcholine so binds to nicotinic cholinergic receptors in the brain (Agonist) |