When a neuron is at rest what is primarily responsible for moving potassium ions into the cell group of answer choices?

The membrane of a neuron is specialized to: keep all types of intercellular chemicals from moving out of the neuron.keep all types of extracellular chemicals from moving into the neuron.control the exchange of chemicals between the inside and outside of the cell.produce chains of fatty acids and proteins.

control the exchange of chemicals between the inside and outside of the cell.

The membrane of a neuron is composed of ___ with ___ embedded in them. carbohydrates; purinesfat molecules; proteinsproteins; neurotransmittersbenzene molecules; carbohydrates

What is the difference in voltage called that typically exists between the inside and the outside of a neuron? concentration gradientgenerator potentialresting potentialshock value

The resting potential is mainly the result of: negatively charged proteins inside the cellpositively charged proteins inside the cellnegatively charged proteins outside the cellpositively charged proteins outside the cell

negatively charged proteins inside the cell

What is the approximate resting potential of the inside of a neuron's membrane, relative to the outside? -70 millivolts+10 millivolts0 millivolts+90 millivolts

The selectivity of a neuron membrane is analogous to: the blood-brain barrierthe action potentialthe resting potentialmyelin

When the neuronal membrane is at rest, the potassium channels: permit potassium ions to pass quickly and easily.permit potassium ions to pass slowly.prohibit any movement of potassium ions.help to open up the sodium channels.

permit potassium ions to pass slowly.

When the neuronal membrane is at rest, the sodium channels: permit sodium ions to pass quickly and easilypermit potassium ions to cross instead of sodiumare closedfluctuate rapidly between open and closed

Which of the following describes selective permeability? Ions can only travel in certain directions across the membrane.Only certain molecules are allowed to cross the membrane freely.Only certain types of stimulation will result in an action potential.All molecules must pass through designated channels.

Only certain molecules are allowed to cross the membrane freely.

When a neuron's membrane is at rest, the concentration gradient tends to move sodium ____ the cell and the electrical gradient tends to move it ___ the cell. into, intointo, out ofout of, intoout of, out of

When a neuron's membrane is at rest, the concentration gradient tends to move potassium ___ the cell and the electrical gradient tends to move it ___ the cell. into, intointo, out ofout of, intoout of, out of

The sodium-potassium pump repeatedly transports ___ sodium ions out of the cell while drawing ___ potassium ions into it. three; twotwo; threeone; threeone; two

Electrical gradients lead to what kind of movements? the general movement of ions into the neuronthe general movement of ions out of the neuronthe movement of ions to areas having the same electrical chargesthe movement of ions to areas having the opposite electrical charges

the movement of ions to areas having the opposite electrical charges

What is meant by the term "concentration gradient" with respect to neurons? Sodium is more concentrated in the dendrites and potassium in the axon.Negative charges are more concentrated outside the cell.Sodium and potassium ions are more concentrated on opposite sides of the membrane.Potassium is more concentrated in the dendrites and sodium in the axon.

Sodium and potassium ions are more concentrated on opposite sides of the membrane.

Concentration gradients lead to what kind of movements? the general movement of ions into the neuronthe general movement of ions out of the neuronthe movement of ions to areas of their highest concentrationsthe movement of ions to areas of their lowest concentrations

the movement of ions to areas of their lowest concentrations

The concentration gradient for potassium tends to: draw potassium into the cell.push chloride out of the cell.push sodium out of the cell.push potassium out of the cell.

push potassium out of the cell.

When the neuron is at rest, what is responsible for moving potassium ions OUT of the cell? a concentration gradientan electrical gradientboth a concentration gradient and an electrical gradientthe sodium-potassium pump

When the neuron is at rest, what is responsible for moving potassium ions into the cell? concentration gradientan electrical gradientthe sodium-potassium pumpboth the sodium-potassium pump and electrical gradient

both the sodium-potassium pump and electrical gradient

When a membrane is at rest, what attracts sodium ions to the inside of the cell? an electrical gradienta concentration gradientboth an electrical gradient and a concentration gradientneither an electrical gradient nor a concentration gradient

both an electrical gradient and a concentration gradient

When the neuron is at rest, what is responsible for moving sodium ions out of the cell? a concentration gradientan electrical gradientboth a concentration gradient and an electrical gradientthe sodium-potassium pump

the sodium-potassium pump

Which of the following is an advantage of having a resting potential? The toxic effects of sodium are minimized inside the cell.No energy is required to maintain it.The cell is prepared to respond quickly to a stimulus.All of the ions are maintained in equal concentrations throughout the cytoplasm.

The cell is prepared to respond quickly to a stimulus.

Ordinarily, stimulation of a neuron takes place: through hyper polarization.at the synapse.in the mitochondria.in the endoplasmic reticulum.

What is the result if a stimulus shifts the potential inside a neuron from the resting potential to a more negative potential? HyperpolarizationDepolarizationan action potentiala threshold

What is the result if a stimulus shifts the potential inside a neuron from the resting potential to a potential slightly closer to zero? hyperpolarizationdepolarizationselective permeabilitya refractory period

The neuron will produce an action potential only if the depolarization exceeds what level? the threshold of excitationthe resting potentialhyperpolarizationthe refractory period

the threshold of excitation

What tends to open the sodium gates across a neuron's membrane? hyperpolarization of the membranedepolarization of the membraneincrease in the sodium concentration outside the neuronpassing the peak of the action potential and entering the refractory period

depolarization of the membrane

Stimulus A depolarizes a neuron just barely above the threshold. Stimulus B depolarizes a neuron to 10 mV beyond threshold. What can we expect to happen? Stimulus B will produce an action potential that is conducted at a faster speed than A.Stimulus B will produce an action potential of greater magnitude than stimulus A.Stimulus B will produce an action potential but stimulus A will not.Stimulus A and stimulus B will produce the same response in the neurons.

Stimulus A and stimulus B will produce the same response in the neurons.

Which of the following actions would depolarize a neuron? decreasing membrane permeability to calciumincreasing membrane permeability to potassiumdecreasing membrane permeability to sodiumincreasing membrane permeability to sodium

increasing membrane permeability to sodium

The action potential of a neuron depends mostly on what movement of ions? sodium ions entering the cellsodium ions leaving the cellpotassium ions entering the cellpotassium ions leaving the cell

sodium ions entering the cell

In the normal course of an action potential: sodium channel remain open for long periods of timethe concentration of sodium equalizes across the membranesodium remains much more concentrated outside than inside the neuronsubthreshold stimulation intensifies the action potential

sodium remains much more concentrated outside than inside the neuron

When the potential across a membrane reaches threshold, the sodium channels: open to let the sodium enter the cell rapidlyclose to prevent sodium from entering the cellopen to let sodium exit the cell rapidlyclose to prevent sodium from exiting the cell

open to let the sodium enter the cell rapidly

During the entire course of events from the start of an action potential until the membrane returns to its resting potential, what is the net movement of ions? sodium in, potassium insodium out, potassium outsodium in, potassium outsodium out, potassium in

A drug that blocks the sodium gates of a neuron's membrane would: decrease the thresholdblock the action potentialcause repeated action potentialseliminate the refractory period

block the action potential

After the peak of an action potential, what prevents sodium ions from continuing to enter the cell? There is no longer a concentration gradient for sodiumThe sodium-potassium pump greatly increases its rate of activityAll the available sodium ions have already entered the cellThe sodium gates in the membrane close

The sodium gates in the membrane close

Just after the peak of the action potential, what movement of ions restores the membrane to approximately the resting potential? Sodium ions enter the cellPotassium ions enter the cellPotassium ions leave the cellSodium ions travel down the axon

Potassium ions leave the cell

A drug that decreases the flow of potassium through the potassium gates of the membrane would: block action potentialsincrease the threshold of the membraneslow the return of the membrane to its resting potentialcause the membrane to be hyperpolarized

slow the return of the membrane to its resting potential

Local anesthetic drugs attach to the sodium channels of the membrane, which: allows sodium ions to enter and stop action potentialprevents potassium ions from entering and stopping action potentialallows potassium ions to enter and stop action potentialprevent sodium ions from entering and stopping action potential

prevent sodium ions from entering and stopping action potential

Which of the following represents the all-or-none law? Every depolarization produces an action potentialEvery hyperpolarization produces an action potentialThe size of the action potential is independent of the strength of the stimulus that initiated itEvery depolarization reached the threshold, even if it fails to produce an action potential

The size of the action potential is independent of the strength of the stimulus that initiated it

The presence of an all-or-none law suggests that neurons can only convey different messages by changing their: rate or pattern of action potentialssize of actions potentialsspeed of action potentialssodium-potassium pump activity

rate or pattern of action potentials

The primary feature of a neuron that prevents the action potential from traveling back from where it just passed is the: concentration gradientrefractory periodsodium potassium pumpphospholipid bilayer

Which feature of a neuron limits the number of action potentials it can produce per second? the thresholdthe refractory periodsaltatory conductionthe length of the axon

A neuron's sodium gates are firmly closed and the membrane cannot produce an action potential during: the absolute refractory periodthe relative refractory perioddepolarizationsaltatory conduction

the absolute refractory period

Where do most action potentials begin? in the dendritesin the cell bodyat the axon hillockat the tip of the axon

What happens once an action potential starts? It is conducted the rest of the way as an electrical current.It needs additional stimulation to keep it going along the axon.It increases in speed as it goes.It is regenerated at other point along the axon.

It is regenerated at other point along the axon.

The presence of myelin and the diameter of the axon: affect the strength and frequency of the stimulusaffect the speed of an action potentialaffect the strength of an action potentialaffect the frequency of an action potential

affect the speed of an action potential

In a myelinated axon, where are sodium gates abundant? in the areas covered my myelinat the nodes of Ranvierthroughout the axononly in the axon hillock

To what does saltatory conduction refer? the production of an action potential by the movement of sodium ionsthe transmission of an impulse along a myelinated axonthe transmission of impulses along dendritesthe transmission of an impulse between one neuron and another

the transmission of an impulse along a myelinated axon

What disease is related to the destruction of myelin sheaths? multiple sclerosiscystic fibrosismyasthenia gravisParkinson's disease

In what way is a myelinated axon that has lost its myelin (through disease) different from an axon that was never myelinated? It has a smaller diameter.It lacks sodium gates along parts of its surface.It has a longer refractory period.It has a much higher threshold.

It lacks sodium gates along parts of its surface.

A local neuron: has an axon approximately a meter longconveys information to other neurons across great distancesis a small neuron with no axon or a very short onehas an axon with many branches far from the cell body

is a small neuron with no axon or a very short one