NTA Cardiovascular Anatomy and Physiology 2 — Questions and Answers
Question 1: Depolarization of the ventricles is represented on the ECG by which waveform?
- P wave
- T wave
- U wave
- QRS complex (Correct answer)
Correct answer: QRS complex
The QRS complex reflects rapid ventricular depolarization, which triggers myocardial contraction.
Question 2: What does the term 'cardiac output' refer to?
- The pressure exerted by the heart on arterial walls
- The volume of blood ejected by one ventricle per minute (Correct answer)
- The percentage of blood ejected per beat
- The heart's resting oxygen consumption
Correct answer: The volume of blood ejected by one ventricle per minute
Cardiac output (CO) equals stroke volume multiplied by heart rate and represents the volume pumped per minute.
Question 3: Which phase of the cardiac cycle represents ventricular contraction?
- Diastole
- Systole (Correct answer)
- Isovolumetric relaxation
- Atrial kick
Correct answer: Systole
Systole is the phase during which the ventricles contract and eject blood into the aorta and pulmonary artery.
Question 4: The 'atrial kick' contributes approximately what percentage of ventricular filling at normal heart rates?
- 5–10%
- 15–30% (Correct answer)
- 40–50%
- 60–70%
Correct answer: 15–30%
Atrial contraction contributes roughly 15–30% of ventricular filling, which becomes especially important when heart rate is elevated.
Question 5: Which valves open during ventricular systole?
- Mitral and tricuspid valves
- Aortic and pulmonic valves (Correct answer)
- Mitral and aortic valves
- Tricuspid and pulmonic valves
Correct answer: Aortic and pulmonic valves
During systole, rising ventricular pressure forces open the aortic and pulmonic (semilunar) valves to eject blood.
Question 6: The refractory period of the cardiac cycle is important in telemetry because stimulation during this phase can:
- Cause sinus bradycardia
- Trigger a life-threatening arrhythmia (R-on-T phenomenon) (Correct answer)
- Lengthen the PR interval
- Slow AV nodal conduction
Correct answer: Trigger a life-threatening arrhythmia (R-on-T phenomenon)
A stimulus falling on the vulnerable T wave (R-on-T) can precipitate ventricular tachycardia or fibrillation.
Question 7: Stroke volume is primarily determined by which three factors?
- Heart rate, blood pressure, and temperature
- Preload, afterload, and contractility (Correct answer)
- Sodium, potassium, and calcium levels
- Respiratory rate, tidal volume, and oxygen saturation
Correct answer: Preload, afterload, and contractility
Stroke volume is governed by preload (filling volume), afterload (resistance to ejection), and myocardial contractility.
NTA Cardiovascular Anatomy and Physiology 2
Depolarization of the ventricles is represented on the ECG by which waveform?