A change in the voltage across a neuron’s plasma membranethat makes the neuron less likely to fire an action potential isa. a change that makes the resting potential less negative.b. an excitatory postsynaptic potential.c. an inhibitory postsynaptic potential.d. a change that lowers the threshold.

A change in the voltage across a neuron’s plasma membranethat makes the neuron less likely to fire an action potential isa. a change that makes the resting potential less negative.b. an excitatory postsynaptic potential.c. an inhibitory postsynaptic potential.d. a change that lowers the threshold.

Concepts of Biology

1st Edition

ISBN:9781938168116

Author:Samantha Fowler, Rebecca Roush, James Wise

Publisher:Samantha Fowler, Rebecca Roush, James Wise

Chapter16: The Body's System

Section: Chapter Questions

Problem 24RQ: Neurons contain ________, which can receive signals from other neurons. a. axons b. mitochondria c....

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Post synaptic neurons membrane potentials are less negative than resting membrane potentials when this occur A. Creates a new set point for the resting membrane potential B. Has a lower propensity to produce an action potential C. Reacts by generating action potential D. Higher chance of reaching the potential threshold
Action potential conduction velocity is more rapid in a myelinated axon than an unmyelinated one because in a myelinated axon: a. the action potential travels as a continuous wave. b. there is a decrease in membrane resistance. c. the action potential jumps along the axon. d. there is an increase in membrane capacitance. e. there is an increase in the ion gradients.
Summationa. is caused by combining two or more graded potentials.b. occurs at the trigger zone of the postsynaptic neuron.c. results in an action potential if it reaches the threshold potential.d. can occur when two action potentials arrive in close succession ata single presynaptic terminal.e. All of these are correct.
The difference in charges across the plasma membrane of anunstimulated neuron is calleda. an EPSP.b. the resting membrane potential.c. an IPSP.d. the graded potential.e. the action potential.
The Na+/K+ ATPase pump is a. not required for action potential firing. b. important for long-term maintenance of resting potential. c. important only at the synapse. d. used to stimulate graded potentials.
Action potentials are normally initiated at the axon hillock because a. there is a particularly high density of voltage-gated sodium channels there. b. threshold potential is lower there than at other sites along the plasma membrane. c. activation of sodium channels at the axon hillock results in a particularly strong inward current and consequent depolarization. d. all of these. e. none of these.
The absolute refractory perioda. limits how many action potentials can be produced during a givenperiod of time.b. prevents an action potential from starting another action potentialat the same point on the plasma membrane.c. is the period of time when a strong stimulus can initiate a secondaction potential.d. Both a and b are correct.e. All of these are correct
At a chemical synapse, an action potential triggers an influx of Ca²+ which .. Select one: O A. triggers the exocytosis of neurotransmitters. O B. interfere directly with IPSPS in the postsynaptic cell. O C. depolarize the synaptic terminal of the presynaptic neuron, causing an excitatory postsynaptic potential (EPSP) in it. D. bind to neurotransmitter receptors on the postsynaptic cell, causing an inhibitory postsynaptic potential (IPSP). O E. cause the fusion of synaptic vesicles with the postsynaptic membrane, releasing neurotransmitters into the synaptic terminals.
The equilibrium potential for K* in neurons is ordinarily nearest- A. the equilibrium potential for Na* B. resting potential C. reversal potential for the EPSP D. the peak of the action potential
During a relative refractory period of an action potential A. Another action potential can be fired, it just takes a greater stimulus for the membrane potential to reach threshold B. Na+ channels are either already open or are inactivated therefore the membrane absolutely can not produce another action potential, no matter how intense the stimulus C. Ca++ flows out of the cell, causing hyperpolarization and a need for a greater stimulus to generate the action potential D. The presynaptic neuron "tells" the postsynaptic neuron about the "relative" strength of signal E. None of the above are correct
The resting membrane potential of a neuron or muscle cell is a. equal to the potassium equilibrium potential. b. equal to the sodium equilibrium potential. c. somewhat less negative than the potassium equilibrium potential. d. somewhat more positive than the sodium equilibrium potential. e. not changed by stimulation.
Which of the following primarily reflects the opening of voltage-gated Na+ channels? A. The resting membrane potential B. The depolarization phase of the action potential C. The threshold potential D. The repolarization phase of the action potential E. All of the above