Muscle Physiology: Membrane Potential and Action Potential

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What is the driving force for the diffusion of uncharged molecules?

Leak permeable channels

Concentration gradient (correct)

Electrical charges

Diffusion potential

What is the main factor that determines the diffusion potential?

Concentration gradient only

Permeability of the membrane only

Electrical charge of the ion

Both concentration gradient and permeability of the membrane (correct)

What is the term for the potential that exactly balances the tendency of an ion to diffuse down its concentration gradient?

Resting potential

Nernst potential

Equilibrium potential (correct)

Diffusion potential

What is the direction of the diffusion of Na+ ions in a solution with a higher concentration of Na+ and a lower concentration of Cl-?

From the side with higher Na+ concentration to the side with lower Cl- concentration Signup and view all the answers

What is the term for the difference in electric potential between the interior and exterior of a biological cell?

Membrane potential Signup and view all the answers

What is the purpose of the leak permeable channels in the membrane?

To maintain the resting membrane potential Signup and view all the answers

Which of the following ions has the highest equilibrium potential?

Ca2+ Signup and view all the answers

What is the result of the diffusion of Na+ ions down its concentration gradient?

A diffusion potential is generated Signup and view all the answers

What is the term for the potential that is maintained by a cell over a long period of time without significant change?

Resting potential Signup and view all the answers

What is the condition required for the generation of a diffusion potential?

A concentration gradient of a charged solute Signup and view all the answers

What is the effect of the movement of a few ions on the concentration of ions in bulk solution?

It does not cause a measurable change in concentration Signup and view all the answers

What is the role of the concentration gradient in the diffusion of Na+ ions?

It drives the diffusion of Na+ ions Signup and view all the answers

What is the equation used to calculate the equilibrium potential of an ion?

Nernst equation Signup and view all the answers

What is the effect of the diffusion of Na+ ions on the membrane potential?

It depolarizes the membrane potential Signup and view all the answers

What is the relationship between the concentration gradient and the diffusion potential?

The concentration gradient generates a diffusion potential Signup and view all the answers

Which cells undergo controlled changes in their membrane potential?

Only neurons and muscle cells Signup and view all the answers

What is the term for the potential that is generated by the movement of only a few ions?

Diffusion potential Signup and view all the answers

What is the purpose of the theoretical membrane in the experiment?

To separate two solutions with different concentrations of Na+ and Cl- Signup and view all the answers

What is the resting potential of nerve fibers when not transmitting nerve signals?

-70 millivolts more negative than the outside Signup and view all the answers

What determines the resting potential of nerve cells?

Diffusion of potassium and sodium through the nerve cell membrane Signup and view all the answers

What is the selectivity of the potassium leak channel for potassium ions compared to sodium ions?

100 times higher Signup and view all the answers

What is the net effect of potassium diffusion on the resting potential?

It makes the potential more negative Signup and view all the answers

What is the function of the sodium-potassium pump in maintaining the resting potential?

It pumps sodium out of the cell Signup and view all the answers

Why do potassium ions move out of the cell through potassium leak channels?

Because of the negative charges inside the cell Signup and view all the answers

What is the relative permeability of the nerve cell membrane to sodium and potassium ions?

Less permeable to sodium ions Signup and view all the answers

What is the primary contributor to the resting potential of nerve cells?

Diffusion of potassium ions Signup and view all the answers

What is the direction of net potassium ion movement through the potassium leak channel?

Out of the cell Signup and view all the answers

What is the term for the moment before an action potential begins?

Resting stage Signup and view all the answers

What is the term for the minimal membrane potential needed to trigger an action potential?

Threshold potential Signup and view all the answers

What type of channels open during depolarization?

Voltage-gated sodium channels Signup and view all the answers

What happens to the membrane potential during repolarization?

It becomes more negative Signup and view all the answers

What is the term for the period when the neuron is in a state of hyperpolarization?

Relative refractory period Signup and view all the answers

What happens to the voltage-gated sodium channels during the absolute refractory period?

They inactivate Signup and view all the answers

What is the result of the rapid diffusion of potassium ions out of the cell?

Repolarization Signup and view all the answers

What is the term for the time needed for voltage-gated sodium channels to revert to their resting state?

Absolute refractory period Signup and view all the answers

What is the term for the state when the neuron is more negative than normal after an action potential?

Hyperpolarization Signup and view all the answers

What is the primary mechanism by which an action potential propagates along the axon?

The depolarization of adjacent portions of the membrane Signup and view all the answers

What is the primary factor that determines the resting membrane potential?

The unequal distribution of ions and the different permeability of the membrane Signup and view all the answers

What is the role of the Na+/K+ ATPase pump in maintaining the resting membrane potential?

It pumps sodium ions out of the cell and potassium ions into the cell Signup and view all the answers

What happens to the resting membrane potential when synaptic signals are received?

It can be changed Signup and view all the answers

How does the Na+/K+ ATPase pump affect the movement of ions across the membrane?

It pumps sodium ions out of the cell and potassium ions into the cell against their concentration gradients Signup and view all the answers

What is the direction of propagation of an action potential along the axon?

It travels in all directions away from the stimulus Signup and view all the answers

What is the mechanism by which the resting membrane potential is maintained?