The made-up drug leakyhose degrades myelin resulting in myelin becoming more porous and therefore a poor insulator. 2.) Which of the following would NOT be an effect of leakyhose? A. Propagation of the action potential would likely slow B. The action potential may degrade because it can’t properly be regenerated C. The action potential would not propagate but would rather reverse directions D. Saltatory conduction may be disrupted E. All of the above effects are consistent with the administration of leakyhose

The made-up drug leakyhose degrades myelin resulting in myelin becoming more porous and therefore a poor insulator. 2.) Which of the following would NOT be an effect of leakyhose? A. Propagation of the action potential would likely slow B. The action potential may degrade because it can’t properly be regenerated C. The action potential would not propagate but would rather reverse directions D. Saltatory conduction may be disrupted E. All of the above effects are consistent with the administration of leakyhose

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter39: Information Flow And The Neuron

Section: Chapter Questions

Problem 7TYK: Which of the following does not contribute to propagation of action potentials? a. As the area...

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Which of the following does not contribute to propagation of action potentials? a. As the area outside the membrane becomes negative, itattracts ions from adjacent regions; as the inside of the membrane becomes positive, it attracts negative ions from nearby in the cytoplasm. These events depolarize nearby regions of the axon membrane. b. The refractory period allows the impulse to travel in only one direction. c. Each segment of the axon prevents the adjacent segments from firing. d. The magnitude of the action potential stays the same as it travels down the axon. e. Up to a limit, increasing the intensity of the stimulus increases the number of action potentials.
1. Action potentials are generated in a region called the _______ which includes the axon hillock and the initial segment of the axon. 2.According to the all-or-nothing principle a.once the electrical impulse reaches a certain level of intensity (its threshold), it fires and moves all the way down the axon without losing any intensity. b.the amount of time a neuron must “rest” in between firing episodes is stable. c.as a person ages, his or her neurological system slows down and the intensity of neural impulses decreases significantly. d.if all the neurons in a network are not integrated, the “message” carried by the neurons will be lost.
1. What could you correctly say about the Bundle of His? a. Changes in its rhythm of firing would be classified as dromotropic effects b. Cells within it rely on calcium-induced calcium release c. Cells within it would participate in inotropic effects d. Cells within it make force 2. Which of the following is/are true regarding all of the action potentials that we have learned about in class thus far? (Hint - the 3 types are neuronal, ventricular, nodal) a. They all have the fast inward sodium current that is responsible for initial depolarization b. They all carry a calcium current c. They all last over 100ms d. They all have a repolarizing potassium current e. All answers are true
3. (3pts) Chelators are compounds that bind tightly to specific ions and prevent them from eliciting a biochemical effect. The drug BAPTA is a chelator of Ca2+ ions. How would injection of BAPTA into a presynaptic neuron affect postsynaptic cells? a. Nothing would happen because postsynaptic potentials are due to Na+, K+ and Cl- ion mediated currents. b. The postsynaptic membrane potentials would be more polar when presynaptic cells are stimulated. c. There would be a reduction in postsynaptic currents upon stimulation of the presynaptic cell. d. Evoked postsynaptic potentials would be normal, but there would be a decrease in the frequency of spontaneous postsynaptic potentials. e. There would not be action potentials fired in presynaptic cells. Page 1 of 6
Which of the following statements is FALSE? a. graded potentials can sum over time and space, action potential cannot b. action potentials have refractory periods, graded potentials do not c. action potentials are all-or-none, graded potentials are not d. graded potentials and action potentials are caused by ions moving through open channels e. all of the above statements are true (if all of the above are true this is the correct answer) ....
Local anesthetics "block" the action potential and therefore do not allow "pain" information to proceed to the brain and spinal cord. In the presence of these molecules (local anesthetics) 'threshold' is essentially "ignored". The molecules most logically work by: 23. a. Decreasing the intracellular [potassium] b. Blocking the opening of the voltage-gated potassium channels c. Decreasing the extracellular [sodium] d. Blocking the opening of the voltage-gated sodium channels
7. Draw a standard action potential compared to an action potential whose voltage gated potassium channels have been inactivated with tetraethylammonium (TEA). a. Draw the curves. Label all axes. b. Describe how and why they are different.
2.Neurons a.What are the 3 types of chemical channels and where on the neuron would they be found? b.What would happen to the membrane potential of a neuron if a sodium chemical channel opened? Would it change the response of the neuron if a potassium channel opened? Explain. c. What is the ultimate explanation of why the action potential only moves in one direction within the neuron? What is the proximate reason for this? Explain! d. What is the difference between stopping a signal from reaching a post-synaptic neuron, and inhibiting the post synaptic neuron? Explain.
4. Illustrate (draw) what an action potential might look like with the following voltage-gated channels present. Briefly explain why these changes may occur. a. Normal sodium voltage-gated channel and a potassium voltage-gated channel (delayed rectifier); classic action potential as seen with the squid giant axon Normal sodium voltage-gated channel and an A channel (KA voltage-gated channel) b. C. Mutant sodium voltage-gated channel ONLY, where the N-terminal inactivation particle is missing d. Mutant sodium voltage-gated channel, where the N-terminal inactivation particle is missing, plus a potassium voltage-gated channel (delayed rectifier)
6. If the action potentials shown in the diagram below occur sequentially and in close temporal proximity, what will be the final result in cell D? In this notation, < indicates an excitatory an inhibitory synapse. Focus on overall effects – excitation and inhibition – don't worry about quantifying responses here. (Hint: you may want to identify what is happening at each cell and then how that will be affected by the activation of the previous cell) synapse and indicates Above Above threshold stimulation Above threshold stimulation threshold stimulation D
Which of the following would most likely suppress an action potential in neurons? Select one: a. increased amount of ATP b. movement of chlorine down its concentration gradient c. active transport of chlorine d. opening of sodium channels e. closing calcium channels Clear my choice
7. Which of the following statements best explains why a neuron's membrane potential rapidly drops during the falling phase of an action potential? a. Potassium enters through voltage-gated sodium channels b. Sodium enters through voltage-gated sodium channels c. The sodium-potassium pump pushes sodium out of the neuron d. Potassium exits through voltage-gated potassium channels e. Sodium exits through voltage-gated sodium channels