Which of the following is a correct statement of the all-or-none principle? Select one: U a. A hyperpolarized membrane always results in the production of an action potential b. When a stimulus is applied, it triggers an action potential in the membrane O C. Action potentials occur in all neurons if a stimulus is applied that lowers the membrane potential d. A given stimulus either triggers a typical action potential or does not produce one at all

Which of the following is a correct statement of the all-or-none principle? Select one: U a. A hyperpolarized membrane always results in the production of an action potential b. When a stimulus is applied, it triggers an action potential in the membrane O C. Action potentials occur in all neurons if a stimulus is applied that lowers the membrane potential d. A given stimulus either triggers a typical action potential or does not produce one at all

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 3TAHL

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Neurons contain ________, which can receive signals from other neurons. a. axons b. mitochondria c. dendrites d. Golgibodies
Action potentials occur when ______. a. potassium gates close b. a stimulus pushes membrane potential to threshold c. sodium-potassium pumps become active d. neurotransmitter is reabsorbed
Ordinarily, a neuron’s trigger zone is activated before any other part ofan axon, so a wave of action potentials occurs as sodium channelsopen in the direction of the synaptic terminal. What would happen ifyou artificially stimulated an axon to reach threshold potential midwayalong its length rather than at the trigger zone?a. Action potentials would occur in the direction of the synapticterminal.b. No action potentials would occur.c. Action potentials would occur in the direction of the trigger zone.d. Both a and c are correct.
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.
Excitatory neurons A and B both synapse with neuron C. Neuron A releasesa neurotransmitter, and neuron B releases the same type and amount ofneurotransmitter plus a neuromodulator that produces EPSPs in neuron C.Action potentials produced in neuron A alone can result in action potentialproduction in neuron C. Action potentials produced in neuron B alone alsocan cause action potential production in neuron C. Which results in moreaction potentials in neuron C, stimulation by only neuron A or stimulationby only neuron B? Explain.
What event triggers an action potential?a. Opening of sodium channelsb. Opening of delayed potassium channelsc. High concentration of negative ions outside the celld. Activation of the sodium–potassium pump5. Ordinarily, a neuron’s trigger zone is activated b
Which of the following conduct sensory impulses to theCNS from receptors in muscle or skin?a. general somatic efferent fibersb. general somatic afferent fibersc. general visceral afferent fibersd. general visceral efferent fibers
What does a mechanically gated channel respond to?a. physical stimulusb. chemical stimulusc. increase in resistanced. decrease in resistance
Which of the following is the most direct result of depolarizingthe presynaptic membrane of an axon terminal?(A) Voltage-gated calcium channels in the membrane open.(B) Synaptic vesicles fuse with the membrane.(C) Ligand-gated channels open, allowing neurotransmittersto enter the synaptic cleft.(D) An EPSP or IPSP is generated in the postsynaptic cell.
. Suppose a particular neurotransmitter causes an IPSP inpostsynaptic cell X and an EPSP in postsynaptic cell Y. A likelyexplanation is that(A) the threshold value in the postsynaptic membraneis different for cell X and cell Y.(B) the axon of cell X is myelinated, but that of cell Y is not.(C) only cell Y produces an enzyme that terminates the activityof the neurotransmitter.(D) cells X and Y express different receptor molecules for thisparticular neurotransmitter.
Which of the following is true regarding the difference between graded and action potentials? a.) Action potential occur only when the surface of the neuron is myelinated, but graded potentials occur in both in both myelinated and non-myelinated neurons. b.) The magnitude of action potential depends on the magnitude of the stimulus, whereas graded potentials are all or none. c.) The magnitude of graded potential depends on the magnitude of the stimulus, whereas action potentials are all or none.
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