What would happen if the voltage-gated sodium and potassium channels open at the same time?

What would happen if the voltage-gated sodium and potassium channels open at the same time?

At the same time, voltage-gated K+ channels open, allowing K+ to leave the cell. As K+ ions leave the cell, the membrane potential once again becomes negative. The diffusion of K+ out of the cell hyperpolarizes the cell, making the membrane potential more negative than the cell’s normal resting potential.

What happens when action potential increases?

As the membrane potential is increased, sodium ion channels open, allowing the entry of sodium ions into the cell. This is followed by the opening of potassium ion channels that permit the exit of potassium ions from the cell.

How did the action potential generated with the unheated rod compare to that generated with the heated rod?

How did the action potential generated with the unheated rod compare to that generated with the heated rod? The action potential generated with the unheated rod was less than the action potential generated by the heated rod. Describe the types of stimuli that generated an action potential.

What is the effect of ether on a nerve impulse?

General anesthetics such as ether and chloroform function in a different fashion. These drugs decrease brain activity by opening K+ channels; thus allowing these ions out of the cell. The neuron becomes hyperpolarized, and is unable to discharge.

What would happen if voltage-gated K+ channels took longer to open?

Answer: Voltage-gated potassium channels open 1 msec after membrane depolarization. If these channels took longer than normal to open, the action potential would be wider, which means that it would take longer to restore the resting membrane potential.

What is the role of the voltage-gated potassium channels?

Voltage-gated potassium channels (VGKC) are transmembrane channels responsible for returning the depolarized cell to a resting state after each nerve impulse. They are, therefore, important in modulating neuronal excitability in the CNS and peripheral nervous system.

What is happening to the electrical potential of a neuron when it generates an action potential?

When a nerve impulse (which is how neurons communicate with one another) is sent out from a cell body, the sodium channels in the cell membrane open and the positive sodium cells surge into the cell. Once the cell reaches a certain threshold, an action potential will fire, sending the electrical signal down the axon.

What was the effect of curare on eliciting an action potential?

What was the effect of curare on eliciting an action potential? Curare had no effect- an action potential was still generated when the nerve was stimulated at threshold voltage.

How does myelination affect nerve conduction velocity explain?

By acting as an electrical insulator, myelin greatly speeds up action potential conduction (Figure 3.14). For example, whereas unmyelinated axon conduction velocities range from about 0.5 to 10 m/s, myelinated axons can conduct at velocities up to 150 m/s.

Why does the K+ conductance turn on slower and last longer than the Na+ conductance?

K+ conductance turns on slower and lasts longer than the Na+ conductance because the membrane is able to depolarize by opening up K+ ion channels. When the K+ equilibrium potential is raised, depolarization occurs. The increase results in achieving the threshold potential and a generation of action potential.

What happens when voltage-gated sodium channels open?

Voltage-gated sodium channels play an important role in action potentials. If enough channels open when there is a change in the cell’s membrane potential, a small but significant number of Na+ ions will move into the cell down their electrochemical gradient, further depolarizing the cell.

Are there voltage dependent changes in Na + permeability?

In addition to voltage-dependent changes in Na + permeability, there are voltage-dependent changes in K + permeability. These changes can be measured with the voltage-clamp technique as well. The figure shown to above indicates the changes in K + conductance as well as the Na + conductance.

How are the action potentials of sodium modified?

As shown in Figure 2.1, action potentials are repeatedly initiated as the extracellular concentration of Na + is modified. As the concentration of sodium in the extracellular solution is reduced, the action potentials become smaller.

How does a voltage clamp amplifier stabilize a membrane potential?

An electronic device known as a voltage-clamp amplifier can “clamp” or stabilize the membrane potential to any desired level and measure the resultant current required for that stabilization. The amount of current necessary to stabilize the potential is proportional to the permeability.

How often can a short action potential change?

If the action potential was about one msec in duration, the frequency of action potentials could change from once a second to a thousand a second. Therefore, short action potentials provide the nerve cell with the potential for a large dynamic range of signaling. Some chemical agents can selectively block voltage-dependent membrane channels.