109. One reason that action potentials are all-or-none is that a. they are always the same size in a given neuron. b. axonal membranes do not allow partial electrical responses to electrical stimuli. c. they must travel long distances without decrement. *d. once the membrane potential is past threshold, the influx of Na+ keeps driving it more positive until the maximum number of Na+ channels is

108. The all-or-none principle of nerve action states that a. the entire length of the nerve conducts an action potential or no part does. *b. an action potential always reaches its maximum strength or it doesn't appear at all. c. all available ions contribute to the rise and fall of the action potential or none do. d. all synapses on a neuron must be active in order for them to excite it.

Each action potential Blank______.Multiple choice question.begins in the synaptic terminal and spreads up the axon to the axon hillockspreads across the entire surface of the membrane so that the entire cell is depolarized at one timeaffects only a small area of the plasma membrane of the cell at a timebuilds upon the previous action potential to create a larger potential change

Complete the sentences describing the events that occur during an action potential.An action potential will not occur unless the membrane potential at the (the initial segment of the axon) reaches a level called .When threshold is reached, of the initial segment open briefly, allowing to diffuse into the cell.As these ions enter the cell, the cell membrane undergoes , with the membrane potential increasing to a peak of approximately +30mV.As the peak of the action potential is reached, the sodium channels close and the open, allowing these ions to diffuse out of the cell.As cations leave the cell, the membrane potential at that part of the membrane once again becomes negative. This phase of the action potential is called , because the resting membrane potential is being reestablished.The membrane potential actually dips lower than -70mV because the potassium channels do not close quickly enough. This phase is called .

As an action potential occurs in one area of the axon, an electrical current to neighboring areas of the membrane initiates ______.Multiple choice question.a graded potentialhyperpolarization of the membraneanother action potential

When thinking about an action potential which one of the following statements is TRUE?Question 10Answera.A stimulus changes the permeability of a "patch" of the membrane, and sodium ions (Na+) diffuse rapidly into the cell.b.During repolarization, sodium ions diffuse rapidly into the cell.c.If a stimulus is strong enough, hyperpolarization causes membrane polarity to be completely reversed, and an action potential is initiated.d.Ionic conditions are restored after repolarization by the actions of the sodium-potassium (Na+-K+) pump, whereby two Na+ ions are ejected for every three K+ ions carried back into the cell.e.The external side of the resting membrane is slightly negative, and its internal side is slightly positive.