answersLogoWhite

0


Want this question answered?

Be notified when an answer is posted

Add your answer:

Earn +20 pts
Q: Why is the membrane potential for 3 K plus and 0 Na plus channels the same as that for 5 K plus and 0 Na plus channels?
Write your answer...
Submit
Still have questions?
magnify glass
imp
Related questions

Do the action potential travel along the axon of a neuron?

fig. 1Formation of an action potentialThe formation of an action potential can be divided into five steps. (1) A stimulus from a sensory cell or another neuron causes the target cell to depolarize toward the threshold potential. (2) If the threshold of excitation is reached, all Na+ channels open and the membrane depolarizes. (3) At the peak action potential, K+ channels open and K+ begins to leave the cell. At the same time, Na+ channels close. (4) The membrane becomes hyperpolarized as K+ ions continue to leave the cell. The hyperpolarized membrane is in a refractory period and cannot fire. (5) The K+ channels close and the Na+/K+ transporter restores the resting potential.


How does a neuron restore a membrane potential following the generation of an action potential?

The hyperpolarization of the membrane potential relative to the resting potential (the undershoot) causes voltage-dependent Potassium conductance (and any Sodium channels not yet inactivated) to turn off, allowing the membrane potential to return to resting level.


Why does regeneration of action potential occurs in one direction?

As the action potential passes an area on the axon, sodium channels are closed, preventing influx of more sodium ions. At the same time, voltage-sensitive potassium channels open, allowing the membrane potential to fall quickly. After this repolarization phase, membrane permeability to potassium remains high, allowing for the "afterhyperpolarization" phase. During this entire period, while the sodium ion channels are forced closed, another action potential cannot be generated except by a much larger input signal. This helps to prevent the action potential from moving backwards along the axon.


Why does regeneration of the action potential occur in one direction?

As the action potential passes an area on the axon, sodium channels are closed, preventing influx of more sodium ions. At the same time, voltage-sensitive potassium channels open, allowing the membrane potential to fall quickly. After this repolarization phase, membrane permeability to potassium remains high, allowing for the "afterhyperpolarization" phase. During this entire period, while the sodium ion channels are forced closed, another action potential cannot be generated except by a much larger input signal. This helps to prevent the action potential from moving backwards along the axon.


What is the hyperpolarization that occurs after repolarizing phase of action potential?

Hyperpolarization occurs because some of the K+ channels remain open to allow the Na+ channels to reset. This excessive amount of K+ causes hyperpolarization so the Na+ channels open to bring the potential back up to threshold.


Why don't the terms depolarization and action potential mean the same thing?

Depolarization occurs when a stimulus opens sodium channels which allow more sodium to go into the membrane making it less negative and more positive (toward reaching threshold). An action potential can only occur once the membrane reaches threshold which means it has reached the level needed through depolarization. An action potential is a brief reversal in polarity of the membrane making the inside more positive and the outside more negative, the reverse occurs again once the membrane reaches resting potential.


Do action potentials always have the same amplitude and the same duration?

Yes, this is due to the all or nothing law that neurons follow: "an excitable membrane either responds to a stimulus with a maximal action potential that spreads nondecrementally throughout the membrane, or it does not respond with an action potential at all." "


What is the correct sequence of events that follows a threshold potential?

§Labor and management§Productivity§Wage levels§Training needs§Local infrastructureMeasuring site potential in step 3 involves determining whether a site can supply adequate resources needed to carry out the proposed business activity. Key issues include:•For many companies the most important resources will be labor and management.•The productivity and wage levels of local labor and managers.•The cost of training local managers, which can mean substantial investments of time and money.•And the efficiency of local infrastructures, including roads, bridges, airports, seaports, and telecommunications systems.


Why is the resting membrane potential the same in both the sensory neuron and the interneuron?

Because it didnt have a stimulus to activate depolarization


Are graded potentials the same as local potentials?

Postsynaptic potentials are changes in the membrane potential of the postsynaptic terminal of a chemical synapse. Graded potentials are changes in membrane potential that vary in size, as opposed to being all-or-none, and are not postsynaptic potentials.


Why is the resting membrane potential the same value in both the sensory neuron and the interneuron?

Because it didnt have a stimulus to activate depolarization


How is it possible for some molecules to be at equilibrium across a biological membrane and yet not be at the same concentration on both sides?

The equilibrium distribution of a molecule across a membrane depends on concentration and membrane potential. A charged molecule will respond to both components of the electrochemical gradient and will distribute accordingly. K+ ions for example, are at equilibrium across the plasma membrane even though they are 30-fold more concentrated inside the cell. the difference in concentration is balanced by the membrane potential, which is more negative on the inside. The membrane potential opposes the movement of cations to the outside of the cell.