Physiology: Action Potential and ECG Tracing

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What is the period during which an action potential cannot be initiated?

Ventricular repolarization

Relative refractory period

Atrial depolarization

Absolute refractory period (correct)

What is the normal sequence of events on an ECG tracing?

QRS complex, P wave, T wave

P wave, QRS complex, T wave (correct)

T wave, QRS complex, P wave

P wave, T wave, QRS complex

What is the intrinsic rate of the Sinoatrial node?

60-100 bpm (correct)

20-40 bpm

100-120 bpm

40-60 bpm

Which wave on the ECG tracing represents ventricular repolarization?

T wave Signup and view all the answers

During which phase of the cardiac action potential does the rapid depolarization occur?

Phase 0 - P wave Signup and view all the answers

What is the term for the return of an abnormal heartbeat to a normal rhythm?

Cardioversion Signup and view all the answers

What is the function of the Bundle of His?

To transmit cardiac action potentials from the AV node to the Purkinje fibers Signup and view all the answers

What is the period during which an action potential can be initiated with a larger than normal stimulus?

Relative refractory period Signup and view all the answers

What is the term for the process by which the blood stops bleeding after an injury?

Hemostasis Signup and view all the answers

What is the role of the Atrioventricular node in the cardiac conduction system?

To pause the electrical impulse to allow action potential to spread across atria for coordinated contraction Signup and view all the answers

During which phase of the cardiac action potential does the increase in Ca++ occur?

Phase 2 - ST segment Signup and view all the answers

What is the intrinsic rate of the Purkinje fibers?

20-40 bpm Signup and view all the answers

What is the role of von Willebrand factor in platelet plug formation?

Binding platelet receptors to the vessel wall Signup and view all the answers

What is the purpose of the intrinsic pathway in blood coagulation?

To initiate clotting in the circulation Signup and view all the answers

What is the role of ADP and TXA2 in platelet plug formation?

Attracting additional platelets to the site of injury Signup and view all the answers

What is the purpose of the prothrombin time (PT) test?

To measure the time it takes for blood to clot via the extrinsic pathway Signup and view all the answers

What occurs during clot retraction?

The edges of the injury are pulled together with actin and myosin Signup and view all the answers

What is the result of clot retraction?

The squeezing of plasma out of the clot Signup and view all the answers