Cardiac electrophysiology

Which is the correct path of electrical impulses through the heart?

• SA node - Purkinje fibers - AV node - AV bundle - bundle branches

• SA node - AV node - Purkinje fibers - AV bundle - bundle branches

• SA node - AV node - bundle branches - AV bundle - Purkinje fibers

• SA node - AV node - AV bundle - bundle branches - Purkinje fibers

What is going on in the heart during the R-wave or QRS complex

• AV node triggers depolarization in ventricle, the main pumping action

• Delay caused by the SA node

• Repolarization of the ventricle 

• SA node triggers depolarization in atria

The main function of the cardiac conduction pathway is:

• To ensure that the heart muscle in the atria and ventricles all contracts at the same time

• To increase and decrease the heart rate in response to exercise

• To ensure coordinated muscle contraction in the chambers and effective pumping of blood

• None of the above

What are the main components of the cardiac conduction system?

• SA node, AV node, AV bundle, bundle branches & Purkinje fibers

• Atria and ventricles (left and right), SA node, AV node, AV bundle, bundle branches & Purkinje fibers

• Aorta, superior and inferior vena cava, pulmonary trunk

• All of the above

All of the following are true about repolarization, EXCEPT

• Is associated with potassium outflow

• Occurs before the plateau phase of the action potential

• Membrane potential returns to resting potential (-90 mV)

The term that refers to the period when another contraction cannot occur in the muscle is: 

• Autorhythmic

• Depolarization

• Refractory

• Hyperpolarisation

Action potentials in neurons are the same in muscle cells.

• True

• False

There is more than one type of action potential used in the heart.

• True

• False

Which of these is not a model that explains heart rate?

• Polarity model

• Slope model

• Contraction model

What is the function of the AV node?

• Limits fibrillation entry into ventricles

• Delays action potentials to allow ventricular filling (functions as a relay-station)

•  Serves as a secondary pacemaker

• All of the above