L9 Action Potential

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What is the primary cause of the membrane potential?

Electrical charges within the cell

Unequal distribution of ions across the cell membrane (correct)

Chemical reactions occurring inside the cell

Diffusion of ions through the cell membrane

Which of the following ions is primarily responsible for the development of the action potential?

Calcium (Ca2+)

Potassium (K+)

Sodium (Na+) (correct)

Chloride (Cl-)

What is the effect of amiodarone on the sodium channels during the action potential?

Amiodarone enhances the inactivation of the sodium channels (correct)

Amiodarone activates the sodium channels, causing further depolarization

Amiodarone has no effect on the sodium channels

Amiodarone blocks the sodium channels, preventing further depolarization

What is the main effect of changes in ion concentrations on the membrane potential?

Changes in ion concentrations can lead to either depolarization or hyperpolarization, depending on the specific ions involved Signup and view all the answers

Which of the following is a key step in the development of the action potential?

Inactivation of sodium channels Signup and view all the answers

What is the primary purpose of the membrane potential?

To generate electrical signals for communication between cells Signup and view all the answers

What does the Nernst equation help determine?

Membrane potential at equilibrium Signup and view all the answers

In which refractory period does a second action potential become impossible even with a strong stimulus?

Absolute refractory period Signup and view all the answers

Why can a stronger stimulus elicit a second action potential during the relative refractory period?

Activation gate open for sodium channels Signup and view all the answers

What is the role of amiodarone in preventing recurrent ventricular tachycardia?

Inactivation of Na+ channels Signup and view all the answers

How does amiodarone impact the membrane potential in the context of ventricular tachycardia treatment?

Prevents depolarization by inactivating Na+ channels Signup and view all the answers

Why is amiodarone specifically useful in treating ventricular tachycardia?

Blocks Na+ channels to prevent rapid depolarization Signup and view all the answers

What is the typical range of the resting membrane potential (RMP) across the membrane of excitable cells?

-10 to -100 mV Signup and view all the answers

Which principle explains the ionic distribution that contributes to the resting membrane potential?

Gibbs-Donnan membrane equilibrium (GDME) Signup and view all the answers

Which ion plays a primary role in the origin of the resting membrane potential?

Potassium (K⁺) Signup and view all the answers

What is the definition of an action potential?

A brief, rapid, and transient increase in the resting membrane potential, causing the cell to become more positive inside than outside Signup and view all the answers

Which types of channels play a dominant role in the generation of an action potential?

Voltage-gated channels Signup and view all the answers

What is the purpose of the Nernst equation in the context of membrane potentials?

It determines the equilibrium potential for an ion Signup and view all the answers

Which of the following statements accurately describes the effect of amiodarone on sodium channels?

It inactivates sodium channels, preventing further action potentials. Signup and view all the answers

What is the primary mechanism by which amiodarone reduces the risk of ventricular tachycardia?

It prolongs the absolute refractory period. Signup and view all the answers

Which of the following statements illustrates the clinical relevance of basic science knowledge?

Understanding action potentials helps explain the mechanism of antiarrhythmic drugs. Signup and view all the answers

Which of the following resources would provide the most relevant information about action potentials?

ScholarRx annotation on action potentials Signup and view all the answers

What is the primary function of the absolute refractory period in cardiac muscle cells?

To prevent the generation of multiple action potentials. Signup and view all the answers