Cardiac Muscle Action Potential Diagram EXPLAINED

The video tutorial by Kevin Tokoph on Catalyst University explains the action potential of cardiomyocytes, distinct from the pacemaker potential. It covers the phases of action potential, including depolarization, plateau, and repolarization, highlighting the role of sodium, potassium, and calcium ions. The plateau phase is unique to cardiac muscle, allowing efficient blood pumping. The tutorial emphasizes the importance of understanding these phases for comprehending cardiac function.

What is the primary difference between the pacemaker potential and the cardiomyocyte action potential?

• Pacemaker potential is for contraction, cardiomyocyte potential is for electrical conduction.

• Both potentials are for contraction.

• Pacemaker potential is for electrical conduction, cardiomyocyte potential is for contraction.

• Both potentials are for electrical conduction.

What is the approximate resting membrane potential of cardiomyocytes?

• 0 millivolts

• +30 millivolts

• -90 millivolts

• -70 millivolts

Which ion channels are responsible for the initial depolarization in cardiomyocytes?

• Chloride channels

• Sodium channels

• Calcium channels

• Potassium channels

What is unique about the plateau phase in the cardiomyocyte action potential?

• It is present in all muscle types.

• It is only found in neurons.

• It is a feature of skeletal muscle.

• It is unique to cardiac muscle.

Why is the plateau phase important for heart function?

• It allows the heart to finish pumping blood efficiently.

• It prevents the heart from contracting.

• It stops blood flow completely.

• It allows the heart to contract faster.

During the repolarization phase, which ion's movement is primarily responsible for returning the membrane potential to resting state?

• Calcium influx

• Potassium efflux

• Sodium influx

• Chloride influx

How can a cardiomyocyte be stimulated to contract again after repolarization?

• By a neuron

• Only by an external electrical device

• By an adjacent cardiomyocyte or a conduction system cell

• By a skeletal muscle cell