Which of the following is the role of axonal Calcium (Ca2+) channels in neuronal communication at the synapse? a) they inhibit the action potential causing it to stop b) Calcium channels have no role in this process c) by allowing calcium to exit the cell, they promote the propagation of action potential across the synapse by creating depolarization d) by blocking calcium entrance, they mediate the contraction of presynaptic axon to facilitate movement e) when they open, calcium enters the presynaptic terminal, promoting fusion of neurotransmitter vesicles with presynaptic membrane, and release of neurotransmitters to the synaptic cleft

Which of the following is the role of axonal Calcium (Ca2+) channels in neuronal communication at the synapse? a) they inhibit the action potential causing it to stop b) Calcium channels have no role in this process c) by allowing calcium to exit the cell, they promote the propagation of action potential across the synapse by creating depolarization d) by blocking calcium entrance, they mediate the contraction of presynaptic axon to facilitate movement e) when they open, calcium enters the presynaptic terminal, promoting fusion of neurotransmitter vesicles with presynaptic membrane, and release of neurotransmitters to the synaptic cleft

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter4: Principles Of Neural And Hormonal Communication

Section: Chapter Questions

Problem 4TAHL: Assume presynaptic excitatory neuron A terminates on a postsynaptic cell near the axon hillock and...

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Assume presynaptic excitatory neuron A terminates on a postsynaptic cell near the axon hillock and presynaptic excitatory neuron B terminates on the same postsynaptic cell on a dendrite located on the side of the cell body opposite the axon hillock. Explain why rapid firing of presynaptic neuron A could bring the postsynaptic neuron to threshold through temporal summation, thus initiating an action potential, whereas firing of presynaptic neuron B at the same frequency and the same magnitude of EPSPs may not bring the postsynaptic neuron to threshold.
What effect would you expect an antagonist that targets the voltage sensing domain of perisynaptic calcium channels of an inhibitory interneuron have on the firing frequency of a finically active neuron that interneuron synapses onto? Explain in details
1.1 What would be the effect of blocking neurotransmitter degradation on neurotransmitter concentration at the synapse? 1.2You are studying an excitatory synapse that is not strong enough to evoke a postsynaptic action potential. Would the probability of a postsynaptic potential increase or decrease after blocking neurotransmitter degradation? 1.3 ) You are studying an excitatory synapse that evokes a postsynaptic action potential. Would the probability of a postsynaptic potential increase or decrease after blocking presynaptic voltage-gated calcium channels?
I have stimulated a neuron with dopamine for a second followed by treating it with cocaine and calcium chelating agent (which chelates out all calcium from the system making them unavailable for function), what will be the effect of such impulse on generating an action potential in the post-synaptic neuron? Will it be different if I pretreat the set of nerve cells with cocaine and calcium chelating agent followed by stimulating the neuron with dopamine? Justify your answer with proper reasoning in brief.
Which of the following combinations of spatial summation of postsynaptic potentials (PSP) would result in an action potential in a typical neuron? The voltage given for each PSP is measured as it reaches the axon hillock. Axon A EPSP 25 mV & axon B IPSP 10 mV Axon A IPSP 25 mV & axon B EPSP 10 mV Axon A IPSP 5 mV & axon B IPSP 5 mV Axon A EPSP 5 mV & axon B EPSP 5 mV
The axon hillock of a neuron reaches the threshold of excitation and the membrane potential becomes completely reversed. Then, suddenly, the membrane potential begins to return to resting membrane potential. What is the event that triggers this return to resting potential? A. Na+ channels close in a voltage-dependent manner B. Na+ channels close in a time-dependent manner C. Na+ channels close in a chemically-dependent manner D. Na+ channels open in a voltage-dependent manner
Which of the following statements about action potentials and information transmission in the synaptic cleft is FALSE? 1. Action potentials determine the amount of neurotransmitters that are released into the synaptic cleft 2.Action potentials ultimately result in more calcium leaving the target cell at the postsynaptic membrane 3. Action potentials determine the duration that neurotransmitters are released into the synaptic cleft 4. Action potentials ultimately result in more calcium entering the neuron at the axon terminal
which one of the following statements is incorrect? a. temporal summation occurs when a single synaptic input is activated twice in succession, with the second postsynaptic potential occurring before the first postsynaptic potential is over. b. blocking voltage-gated k* channels in the presynaptic membrane of a typical chemical synapse is likely to reduce the amount of neurotransmitter released in response to a single action potential in the presynaptic axon. c. in the optic tectum of the hunting rattlesnake, spatial summation is used to combine inputs from visual and thermoreceptive layers in order to make a decision whether to strike at a mouse-like object. d. a single type of neurotransmitter can have different postsynaptic actions depending on the type of receptor to which it binds.
Neurons, particularly those in the brain, receive multiple excitatory and inhibitory signals. What is the name of the extension of the neuron at which such signals are received? How does the neuron integrate these signals to determine whether or not to generate an action potential?
Which of the following would occur if a neuron was experimentally stimulated simultaneously at both ends? The action potentials would pass in the middle and travel to the opposite ends The action potentials would stop as they meet in the middle. The stronger action potential would override the weaker action potential. Summation would occur when the action potentials meet in the middle, resulting in a larger action potential.
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