CCT - Certified Cardiographic Technician Cardiovascular Anatomy and Physiology Questions and Answers 1 — Questions and Answers
Question 1: A red blood cell is in the right atrium. Which of the following represents the correct path it will take through the heart's valves to reach the systemic circulation via the aorta?
- Mitral -> Aortic -> Tricuspid -> Pulmonic
- Tricuspid -> Pulmonic -> Mitral -> Aortic (Correct answer)
- Tricuspid -> Aortic -> Mitral -> Pulmonic
- Pulmonic -> Tricuspid -> Aortic -> Mitral
Correct answer: Tricuspid -> Pulmonic -> Mitral -> Aortic
Deoxygenated blood flows from the right atrium, through the tricuspid valve to the right ventricle, then through the pulmonic valve to the lungs. Oxygenated blood returns to the left atrium, passes through the mitral valve to the left ventricle, and is finally ejected through the aortic valve into the systemic circulation.
Question 2: A patient's ECG shows a complete absence of P waves and a regular, narrow-complex rhythm at a rate of 50 beats per minute. Which structure has most likely taken over as the primary pacemaker of the heart?
- Sinoatrial (SA) node
- Purkinje fibers
- Bundle of His
- Atrioventricular (AV) node (Correct answer)
Correct answer: Atrioventricular (AV) node
The SA node, the heart's primary pacemaker, normally fires at 60-100 bpm and generates the P wave. Its failure causes a secondary or escape pacemaker to take over. The AV node (or AV junction) has an intrinsic firing rate of 40-60 bpm. When it acts as the pacemaker, it produces a junctional escape rhythm, characterized by a regular, narrow-QRS rhythm without preceding P waves, which matches the scenario. Purkinje fibers have a slower intrinsic rate (20-40 bpm) and produce a wide QRS complex.
Question 3: An ECG shows ST-segment elevation in leads II, III, and aVF, indicating an injury to the inferior wall of the left ventricle. Occlusion of which coronary artery is the most likely cause of this finding?
- Right Coronary Artery (RCA) (Correct answer)
- Left Anterior Descending (LAD) artery
- Circumflex (Cx) artery
- Left Main Coronary Artery
Correct answer: Right Coronary Artery (RCA)
In approximately 80-90% of individuals (a right-dominant circulation), the Right Coronary Artery (RCA) gives rise to the posterior descending artery, which is the primary blood supply to the inferior wall of the left ventricle. Therefore, an occlusion of the RCA is the most common cause of an inferior wall myocardial infarction, which is visualized by ECG changes in the inferior leads (II, III, and aVF).
Question 4: Which layer of the heart wall is composed of cardiac muscle and is primarily responsible for the heart's pumping action?
- Endocardium
- Pericardium
- Myocardium (Correct answer)
- Epicardium
Correct answer: Myocardium
The myocardium is the thick, muscular middle layer of the heart wall. Its coordinated contraction (systole) is responsible for the powerful pumping action that ejects blood from the ventricles. The endocardium is the inner lining, the epicardium is the outer layer of the heart wall, and the pericardium is the protective sac surrounding the heart.
Question 5: On a standard ECG tracing, which waveform represents the electrical activation and depolarization of the ventricular myocardium?
- P wave
- T wave
- U wave
- QRS complex (Correct answer)
Correct answer: QRS complex
The QRS complex represents the rapid depolarization of the right and left ventricles. This large electrical event triggers the mechanical contraction (systole) of the ventricles. The P wave represents atrial depolarization, and the T wave represents ventricular repolarization.
Question 6: A patient at rest has a heart rate of 70 beats per minute and a stroke volume of 60 mL per beat. What is the patient's cardiac output?
- 1.16 L/min
- 4.2 L/min (Correct answer)
- 3.6 L/min
- 7.0 L/min
Correct answer: 4.2 L/min
Cardiac Output (CO) is calculated by multiplying Heart Rate (HR) by Stroke Volume (SV). The formula is CO = HR × SV. In this case, CO = 70 beats/min × 60 mL/beat = 4200 mL/min. To convert this to liters per minute, divide by 1000, which equals 4.2 L/min.
CCT - Certified Cardiographic Technician Cardiovascular Anatomy and Physiology Questions and Answers 1
A red blood cell is in the right atrium.
Which of the following represents the correct path it will take through the heart's valves to reach the systemic circulation via the aorta?