PHYSIOLOGY
SYNAPTIC PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Blocking the voltage-gated channels causes the synaptic vesicles to release their neurotransmitters within the presynaptic cell thus reversing the direction of the impulse.
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Elevated levels of cadmium block the ligand-gated ion channels on the postsynaptic membrane that prevents neurotransmitters from binding.
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Elevated cadmium levels cause synaptic vesicles to fuse with the presynaptic membrane thus releasing their neurotransmitters into the synapse triggering an impulse
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Elevated cadmium levels prevent the influx of Ca2+ ions into the postsynaptic cell that prevents the release of neurotransmitters into the synapse.
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Detailed explanation-1: -When an action potential reaches the presynaptic terminal, it causes neurotransmitter to be released from the neuron into the synaptic cleft, a 20–40nm gap between the presynaptic axon terminal and the postsynaptic dendrite (often a spine).
Detailed explanation-2: -The action potential travels down the axon and reaches the presynaptic terminal depolarizing the membrane in the pre synaptic terminal. The depolarization causes the voltage gated Ca2+ channels to open allowing the influx of Ca2+ that signals the release of neurotransmitter into the synaptic cleft.
Detailed explanation-3: -The depolarization, also called the rising phase, is caused when positively charged sodium ions (Na+) suddenly rush through open voltage-gated sodium channels into a neuron. As additional sodium rushes in, the membrane potential actually reverses its polarity.
Detailed explanation-4: -When the presynaptic membrane is depolarized, voltage-gated Ca2+ channels open and allow Ca2+ to enter the cell. The calcium entry causes synaptic vesicles to fuse with the membrane and release neurotransmitter molecules into the synaptic cleft.