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phils questions

Hannah Miller English 150 cards

Cards in this deck (150)

  1. 1Cells have a charge across their membrane with the inner layer of the plasma membrane having a _____ charge?negative
  2. 2Sodium and potassium ions are asymmetrically distributed across the membrane so that, when compared with the interstitial fluid, the cytoplasm:Has a lower concentration of sodium and a higher concentration of potassium
  3. 3Consider the forces pushing potassium across the membrane of a resting cell.The electrical gradient draws potassium into the cell while the chemical gradient pushes it out
  4. 4The Na+/K+ATPase pump pushes:3 sodium ions out the cell in exchange for 2 potassium in
  5. 5In a resting nerve cell, potassium ions diffuse through membrane channels:Out of the cell, that is down their concentration gradient
  6. 6What does the line on the computer screen represent?The potential difference between 2 probes
  7. 7Which of the following solutions has the lowest concentration of potassium?5 mEq K+/L
  8. 8Which of the following solutions has the greatest concentration of potassium?100 mEq K+/L
  9. 9Which of the following solutions acted as a control for this experiment?normal saline
  10. 10The microelectrode was stuck in several different regions of the muscle during the experimental procedure to:Gather data from different muscle fibers within the same muscle
  11. 11What was the relationship between the membrane potential and the concentration of potassium outside the cell?The membrane potential became less negative (depolarized) when the extracellular concentration of potassium was increased.
  12. 12Look at your data. What was the average membrane potential when the muscle fibers were bathed in a solution with a potassium concentration of 5 mEq K+/L?About -65 mV.
  13. 13What was the average membrane potential when the muscle fibers were bathed in a solution with a potassium concentration of 10 mEq K+/L?About -55 mV.
  14. 14If the action potential threshold of a muscle fiber is -50 mV, which [K+] could ultimately produced an action potential within the muscle fibers of a crayfish?About 20 mEq K+/L.
  15. 15What do you think would happen to a muscle that is bathed in a solution with 5 mEq K+/L if the solution suddenly changed to having 20 mEq K+/L?the muscle would contract.
  16. 16In a resting cell, the permeability of the membrane to sodium is:less than that to potassium.
  17. 17Sodium ions are asymmetrically distributed across the cell membrane so that the concentration of sodium within the cytoplasm of the cell:is LOWER than that of the interstitial fluid outside the cell.
  18. 18The Na+/K+ ATPase pump pushes sodium:out of the cell so that the concentration of sodium is greater outside the cell.
  19. 19What characteristics do the forces pushing sodium across the membrane of a resting cell have?The electrical gradient and the chemical gradient both draw sodium into the cell.
  20. 20Sodium and potassium ions are asymmetrically distributed across the membrane so that, when compared with the interstitial fluid outside the cell, the cytoplasm inside the cell:has a lower concentration of sodium and a higher concentration of potassium.
  21. 21In response to the microelectrode tip being placed inside a muscle fiber of a crayfish, the blue line on the computer screen:deflected down
  22. 22The amount of line deflection depended on:the size of the membrane potential.
  23. 23Several different locations were used when inserting the microelectrode tip. This was to gather data from:different muscle fibers in the crayfish muscle.
  24. 24In this experiment, the Ringer’s solution was used:as the experimental value that changes sodium concentration.
  25. 25While the microelectrode is placed inside of the muscle fiber, the indifferent electrode is placed:in the saline solution outside of the muscle.
  26. 26What was the relationship between the membrane potential and the concentration of sodium outside the cell?The membrane potential became more negative (hyperpolarized) when the concentration of sodium was decreased.
  27. 27Look at your final graph. What is the slope of the line? (The value has been written on the graph; the slope is the number immediately to the left of “x”.)About 8.
  28. 28If the concentration of sodium decreased in the Ringer’s solution by a factor of 10 (say from 100 to 10 mEq Na+/L), what would happen to the membrane potential?The membrane would become about 8 mV more negative.
  29. 29In another experiment, increasing the level of potassium in the Ringer’s solution by a factor of 10 (say from 5 to 50) caused the membrane potential to increase by about 30 mV. This means that, when compared with sodium:potassium has a greater effect on the membrane potential.
  30. 30A muscle contraction is initiated by an action potential, whose threshold is 15 mV less negative with respect to resting potential. What do you think would happen to a muscle if you changed the Ringer’s solution it was in from 20 mEq Na+/L to 200 mEq Na+/L?The muscle would exhibit no visible response.
  31. 31In this experiment, action potentials are recorded from:a group of axons in the sciatic nerve of a frog that conduct action potentials at the same speed.
  32. 32Consider the forces pushing sodium across the membrane of a resting cell.The electrical gradient and the chemical gradient both draw sodium into the cell.
  33. 33During an action potential, the inside of the cell initially goes from negative to positive. This membrane depolarization, in which the inside of the cell becomes positive, is produced by:sodium moving into the cell.
  34. 34After the initial increase in membrane potential to a positive voltage, the membrane potential returns to resting levels because:potassium moves out of the cell.
  35. 35During the action potential, voltage-gated channels open so that:the sodium channels are fully open before the potassium channels.
  36. 36In this experiment, a compound action potential is produced in the frog sciatic nerve by:applying any stimulus at or above 0.4 V to the nerve.
  37. 37The measurements are called compound action potentials because:the measured response correlates to how many axons are being stimulated.
  38. 38Why was the saline drained from the nerve chamber before the nerve was stimulated?To prevent the current from passing through the saline rather than between the nerve and electrodes.
  39. 39During this experiment, action potentials were produced in the frog sciatic nerve by electrical stimuli that:stimulated the electrodes placed on the nerve.
  40. 40The amplitude of each line tracing on the computer screen represented:the response of the nerve to the stimulus administered.
  41. 41A low voltage electrical stimulus (0 or 0.1 volts) produced no response on the screen because:the stimulus was below threshold, so it did not produce any action potentials.
  42. 42The smallest response recorded, with a stimulus around 0.3 volts, was produced because:only a few axons were brought to threshold, so only these few axons produced an action potential.
  43. 43Increasing the stimulus voltage from about 0.3 to 1 volt increased the amplitude of the CAP. This observation can be explained by:an increase in the number of axons brought to threshold and producing a single action potential.
  44. 44CAP amplitude reached a maximum when the stimulus voltage was above a certain level. This certain level of stimulus voltage was:around 1 volt.
  45. 45A high-voltage stimulus produced a CAP with maximum amplitude because:all of the axons in the nerve produced an action potential.
  46. 46In this experiment, action potentials are recorded from:a group of axons in the sciatic nerve of a frog that conduct action potentials at the same speed.
  47. 47Consider the forces pushing sodium across the membrane of a resting cell.The electrical gradient and the chemical gradient both draw sodium into the cell.
  48. 48During an action potential, the inside of the cell initially goes from negative to positive. This membrane depolarization, in which the inside of the cell becomes positive, is produced by:sodium moving into the cell.
  49. 49After the initial increase in membrane potential to a positive voltage, the membrane potential returns to resting levels because:potassium moves out of the cell.
  50. 50During the action potential, voltage-gated channels open so that:the sodium channels are fully open before the potassium channels.
  51. 51In this experiment, a compound action potential is produced in the frog sciatic nerve byapplying any stimulus at or above 0.4 V to the nerve.
  52. 52The measurements are called compound action potentials because:the measured response correlates to how many axons are being stimulated.
    multiple measurements are added together.
  53. 53Why was the saline drained from the nerve chamber before the nerve was stimulated?To prevent the current from passing through the saline rather than between the nerve and electrodes.
  54. 54During this experiment, action potentials were produced in the frog sciatic nerve by electrical stimuli that:stimulated the electrodes placed on the nerve.
  55. 55The amplitude of each line tracing on the computer screen represented:the response of the nerve to the stimulus administered.
  56. 56A low voltage electrical stimulus (0 or 0.1 volts) produced no response on the screen because:the stimulus was below threshold, so it did not produce any action potentials.
  57. 57The smallest response recorded, with a stimulus around 0.3 volts, was produced because:only a few axons were brought to threshold, so only these few axons produced an action potential.
  58. 58Increasing the stimulus voltage from about 0.3 to 1 volt increased the amplitude of the CAP. This observation can be explained by:an increase in the number of axons brought to threshold and producing a single action potential.
  59. 59CAP amplitude reached a maximum when the stimulus voltage was above a certain level. This certain level of stimulus voltage was:around 1 volt.
  60. 60A high-voltage stimulus produced a CAP with maximum amplitude because:all of the axons in the nerve produced an action potential.
  61. 61An action potential is produced when the membrane potential reaches “threshold.” What is “threshold”?A membrane potential that is less negative (depolarized) than resting potential
  62. 62During an action potential, voltage-gated sodium channels fully open:before the voltage-gated potassium channels are fully open.
  63. 63All neurons have thin extensions along which action potentials can travel quickly and over long distances. These extensions of the neuron are called:axons.
  64. 64Many neurons have a myelin sheath around their axons. Myelin is formed by:glial cells.
  65. 65In myelinated axons, action potentials take place:at the nodes of Ranvier, where the membrane is exposed to the extracellular fluid.
  66. 66What was the conduction velocity of the CAP at 22 degrees Celsius?Between 25 and 35 m/s
  67. 67What was the conduction velocity of the CAP at 10 degrees Celsius?Between 15 and 20 m/s
  68. 68What was the effect of cooling on the duration (width) of the compound action potential (CAP)?Cooling increased the duration of the CAP.
  69. 69What was the effect of cooling on the time delay between the stimulus and the CAP?Cooling increased the time delay.
  70. 70What was the effect of cooling on the conduction velocity of the CAP?Cooling decreased conduction velocity.
  71. 71What is the effect of cooling on the rate of enzymatic action?Cooling decreases the rate of enzymatic action.
  72. 72Ion channels and enzymes are both proteins. If cooling decreases the rate of enzymatic activity, what do you think cooling does to the rate that channels open and close?Cooling decreases the rate that channels open and close.
  73. 73If channels opening and closing are temperature sensitive, what do you think happens to the rate of membrane potential change when the nerve is cooled?The channels open and close more slowly in the cold, so the resultant membrane potential change takes place slower.
  74. 74If cooling slows channel function and membrane potential changes, what will be the effect of cooling on the duration of the action potential?The duration of the action potential will be increased.
  75. 75If cooling increases the time taken for the membrane to reach threshold and produce an action potential, what will be the effect of cooling on the time taken for the transmission from node to node in a myelinated axon?Cooling increases the time for action potentials to travel between nodes, so conduction velocity will be slower.
  76. 76Voltage-gated sodium channels close quickly after they open because:of an inherent property of the sodium channels.
  77. 77Voltage-gated sodium channels open and then quickly close. At this point:the sodium channels are inactivated and cannot reopen.
  78. 78Voltage-gated potassium channels close because:the membrane repolarizes back to resting.
  79. 79During the absolute refractory period:that region of the neuron cannot produce an action potential.
  80. 80Action potentials produced during the relative refractory period are smaller than the initial response because:some voltage-gated potassium channels are still open.
  81. 81Increasing the stimulus voltage from about 0.3 to 1 volt increased the amplitude of the CAP. This observation can be explained by:an increase in the number of axons brought to threshold and producing a single action potential
  82. 82A high-voltage stimulus produced a CAP with maximum amplitude because:all of the axons in the nerve produced an action potential.
  83. 83Compare the amplitude of the single CAP with the second CAP when the time interval between the two stimuli was 7 milliseconds.The two values are about the same.
  84. 84Look at your data. What happened to the amplitude of the second compound action potential when the time interval between the two stimuli was increased from 7 to 9 milliseconds?CAP amplitude stayed about the same.
  85. 85Look at your data. What happened to the amplitude of the second CAP when the time interval between the two stimuli was decreased from 7 to 3 milliseconds?CAP amplitude decreased.
  86. 86Look at your data. What was the longest time interval when the second CAP was smaller than those recorded at an interval greater than 7 milliseconds?About 6.5 milliseconds
  87. 87The amplitude of an action potential produced during the relative refractory period is smaller because:some voltage-gated potassium channels that were opened by the previous action potential remain open.
  88. 88During the relative refractory period, the stimulus needed to reach threshold must be greater for an action potential to be generated. In this lab, this resulted in a reduction in the amplitude of the second CAP because:fewer axons were firing during the second CAP.
  89. 89Look at your data. Was there a time interval in which no second CAP was recorded? This is the absolute refractory period.About 1 millisecond
  90. 90During the absolute refractory period, no second CAP was recorded because:the voltage-gated sodium channels are inactivated, so they cannot open to produce an action potential.
  91. 91During an action potential, the cell membrane:depolarizes and becomes positive.
  92. 92Membrane depolarization produces an action potential because:it opens voltage-gated sodium channels in the membrane.
  93. 93During an action potential, voltage-gated sodium channels open:before voltage-gated potassium channels.
  94. 94Voltage-gated sodium channels close quickly after they open because:sodium channels inherently close soon after they open.
  95. 95Voltage-gated potassium channels close because:the membrane repolarizes back to resting.
  96. 96The voltage clamp used in this experiment is used to measure:currents that flow across a membrane.
  97. 97The giant squid axon is used in this experiment because:it is large enough to place a wire along its length to apply current across the membrane, it can accommodate the voltage clamp apparatus, it is large enough to place a wire along its length to measure membrane potential
  98. 98Before initiating the voltage clamp, the membrane potential of the giant squid axon was resting at a preset value of:-60 mV.
  99. 99The voltage clamp applied equal and opposite current to keep the membrane potential at:0 mV.
  100. 100Keeping the membrane potential at 0 mV will:allow current to flow, open voltage-gated sodium channels, open voltage-gated potassium channels
  101. 101The original line tracing consisted of:an initial inward current (in the yellow area) and then an outward current (in the green area).
  102. 102Which current was abolished when TEA was injected into the axon?The outward current
  103. 103If TEA blocks voltage-gated potassium channels in the giant squid axon, which cations flow out of the cell and carry the outward current?potassium
  104. 104The application of TTX to the solution bathing the axon changed the line tracing by abolishing:the initial inward current.
  105. 105If TTX blocks the voltage-gated sodium channels in the giant squid axon, which cation flows into the cell and carries the inward current?sodium
  106. 106During an action potential, which ion enters the presynaptic axon terminal to initiate vesicle release?calcium
  107. 107At the neuromuscular junction, an increase in the amount of neurotransmitter released would produce:a larger EPSP
  108. 108The number of vesicles released by an action potential depends upon:the number of vesicles available AND the probability of vesicle release.
  109. 109Synaptic depression can be seen when:the second EPSP is smaller than the first. It is due to the release of fewer synaptic vesicles.
  110. 110Synaptic facilitation can be seen when:the second EPSP is larger than the first. It is due to an increase in the number of vesicles released.
  111. 111Look at your data. Which statement accurately describes one of the relationships between the amplitude of the paired EPSPs?If the first EPSP was small, the second exhibited facilitation (i.e., EPSP #2 was larger).
  112. 112Some responses exhibited synaptic facilitation, where EPSP #2 was larger than EPSP #1. During synaptic facilitation, EPSP #2 was produced by neurotransmitter being released by:more synaptic vesicles than EPSP #1.
  113. 113Synaptic facilitation is produced by a higher concentration of calcium in the axon terminal during the second response. The calcium concentration is higher because:some calcium remains in the terminal from the first presynaptic action potential. This residual calcium adds to the calcium that enters during the second presynaptic action potential.
  114. 114Calcium enters the axon terminal to initiate vesicle release and then is slowly removed. If EPSPs were produced at a closer interval, there would be more residual calcium, so:the second action potential would release more vesicles.
  115. 115Look at your data. Which statement accurately describes one of the relationships between the amplitude of the paired EPSPs?If the first EPSP was large, the second exhibited depression (i.e., EPSP #2 was smaller).
  116. 116If all other variables remain constant, when two action potentials enter the axon terminal and produce a pair of EPSPs in the muscle fiber, the larger EPSP is produced by neurotransmitter being released by:more synaptic vesicles.
  117. 117In a chemical synapse that exhibits depression, which response is produced by the release of neurotransmitter by more synaptic vesicles?(The larger) EPSP #1
  118. 118Look at your data. When compared with synapses that exhibit facilitation, synapses that show depression have larger EPSP #1 and smaller EPSP #2 because:the response is produced by the release from fewer synaptic vesicles in EPSP #2.
  119. 119During synaptic depression, the first action potential causes release from a large number of synaptic vesicles to produce EPSP #1. As a result of this:the number of vesicles available for release is reduced for subsequent EPSPs.
  120. 120During synaptic depression, the second EPSP is smaller than the first because:there are fewer vesicles available, there is insufficient time to replenish the vesicle number, AND the level of calcium in the axon terminal is greater than that of EPSP #1.
  121. 121At the neuromuscular junction, the motor neuron axon is:the presynaptic cell.
  122. 122At the neuromuscular junction, the muscle is:the postsynaptic cell.
  123. 123An excitatory postsynaptic potential (EPSP):depolarizes the membrane.
  124. 124The time course of the presynaptic action potential:is shorter than the time course of the EPSP.
  125. 125Temporal summation:may produce a larger membrane depolarization than one EPSP, may depolarize the membrane to threshold, may be produced by a pair of action potentials in the same motor axon
  126. 126The line deflections on the computer screen represent:depolarization in the muscle cell membrane.
  127. 127depolarization in the muscle cell membrane.one motor neuron stimulating the muscle twice.
  128. 128Temporal summation is demonstrated in the muscle by:changing the time interval between the two stimuli.
  129. 129In this experiment, the longest time interval between the two stimuli was:200200 ms
  130. 130In this experiment, the shortest time interval between the two stimuli was:220 ms
  131. 131Look at your Journal data table. Of these choices, which time interval indicated no difference (i.e., no temporal summation) in the membrane potential after EPSP #2 compared to EPSP #1?200 ms
  132. 132Since there was no measurable difference in depolarization of EPSP#1 plus EPSP#2 at 200 ms, this means that:temporal summation did not occur.
  133. 133Look at your results. What was the longest time interval when the total amount of depolarization was greater than that recorded at an interval of 200 ms?120 ms
  134. 134According to your data, what happened to the total amount of membrane depolarization when the time interval was decreased from 120 ms?The total amount of membrane depolarization continued to increase.
  135. 135If the muscle fibers in this preparation generated action potentials at a threshold of -60 mv, what would be the longest time interval required for the two EPSPs to reach threshold?40 ms
  136. 136At the neuromuscular junction, the:motor neuron is the presynaptic cell, and the muscle is the postsynaptic cell.
  137. 137An action potential is produced in an excitable cell when the membrane potential:is depolarized to or above threshold level.
  138. 138At the neuromuscular junction:an action potential in the motor nerve produces an action potential in the muscle fibers it supplies.
  139. 139An action potential in any of the presynaptic cells produces only single EPSPs in the postsynaptic cell. This means that:the EPSPs must act together, showing summation, to produce an action potential.
  140. 140Two EPSPs are produced at about the same time and show summation. When the two EPSPs are produced by different cells, this is called:spatial summation
  141. 141Scroll through your data in the Journal. What was the lowest stimulus voltage that produced an EPSP in any of the muscle fibers?0.4 volts
  142. 142Scroll through your data in the Journal. The motor axon with the lowest threshold required a stimulus of 0.4 volts to produce an action potential. The amplitude of the EPSP in the fibers supplied by this axon:varied from fiber to fiber.
  143. 143The motor neuron that produced an action potential in response to a 0.4-volt stimulus did not produce an EPSP in some muscle fibers. This can be explained because:the motor neuron does not make a synaptic connection with those muscle fibers.
  144. 144In some fibers, the EPSP increased in size (or appeared to have no response at 0.4 volts) when the stimulus voltage was:0.7 volts
  145. 145In some fibers, the 0.7-volt stimulus increased the size of the EPSP. This increase in EPSP amplitude was caused by:an action potential in a second motor axon.
  146. 146Looking at the varying levels of EPSPs generated, how many motor neurons were activated during this experiment?Four motor neurons were activated.
  147. 147A muscle fiber showed a change in EPSP amplitude at 0.4 volts, 0.7 volts, and 0.9 volts. This suggests that the muscle fiber is supplied by:Three motor axons.
  148. 148A muscle fiber showed a change in EPSP amplitude at 0.4 volts, 0.7 volts, 0.9 volts, and 1.1 volts. This suggests that the muscle fiber was supplied by:Four motor axons.
  149. 149A muscle fiber produced an action potential at a stimulus voltage of 0.9 volts. Can you tell whether that muscle fiber was supplied by the motor axon that was stimulated by a 1.1-volt stimulus?No; the action potential will not be affected by the spatial summation created by the last motor neuron.
  150. 150Increasing the stimulus voltage produced an action potential in more motor axons. The EPSPs showed spatial summation as more motor axons were recruited so that the EPSP:increased in amplitude as more axons that supplied the muscle fiber produced an action potential.

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Flashcards on phils questions , created by Hannah Miller on 13/11/2020.
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