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CCT (ASQ) practice questions

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Question 1Cardiac Anatomy and Physiology

Which chamber of the heart receives oxygenated blood returning from the pulmonary veins?

  1. Right atrium
  2. Right ventricle
  3. Left ventricle
  4. Left atrium Correct answer.

Explanation

Pulmonary veins carry oxygenated blood from the lungs back to the left atrium, which then empties into the left ventricle. The right side of the heart handles deoxygenated systemic venous return.

Question 2Cardiac Anatomy and Physiology

The valve located between the left atrium and left ventricle is the:

  1. Aortic valve
  2. Mitral valve Correct answer.
  3. Tricuspid valve
  4. Pulmonary valve

Explanation

The mitral (bicuspid) valve guards the left atrioventricular opening. The tricuspid valve occupies the right atrioventricular opening, and the semilunar valves sit at the ventricular outflow tracts.

Question 3Cardiac Anatomy and Physiology

Blood draining from the coronary circulation enters the right atrium mainly through which structure?

  1. Chordae tendineae
  2. Coronary sinus Correct answer.
  3. Fossa ovalis
  4. Ligamentum arteriosum

Explanation

Most cardiac venous blood collects in the coronary sinus, which opens into the right atrium near the inferior vena cava. The other listed structures are non-venous landmarks or valve components.

Question 4Cardiac Anatomy and Physiology

The normal resting pacemaker of the heart is the:

  1. Sinoatrial node Correct answer.
  2. Atrioventricular node
  3. Bundle of His
  4. Purkinje fibers

Explanation

The sinoatrial node in the upper right atrium has the fastest intrinsic firing rate and normally sets the sinus rhythm. Lower pacemakers fire more slowly and act as backup.

Question 5Cardiac Anatomy and Physiology

Which vessel carries deoxygenated blood from the right ventricle to the lungs?

  1. Superior vena cava
  2. Pulmonary artery Correct answer.
  3. Pulmonary vein
  4. Aorta

Explanation

The pulmonary artery is the only artery in the adult body that carries deoxygenated blood, delivering it from the right ventricle to the lungs. Pulmonary veins return oxygenated blood to the left atrium.

Question 6Cardiac Anatomy and Physiology

The thickest muscular wall of the heart is found in the:

  1. Right ventricle
  2. Left atrium
  3. Left ventricle Correct answer.
  4. Right atrium

Explanation

The left ventricle must generate the highest pressure to drive blood through the systemic circulation, so its myocardium is the thickest. Atrial walls are thin because atria only fill the ventricles.

Question 7Cardiac Anatomy and Physiology

The fibrous skeleton of the heart primarily serves to:

  1. Store calcium for contraction
  2. Anchor the valves and insulate atria from ventricles Correct answer.
  3. Carry oxygen to the myocardium
  4. Generate the action potential

Explanation

The dense connective tissue of the fibrous skeleton supports the valve rings and electrically insulates the atria from the ventricles, forcing conduction through the AV node. It is not excitable tissue.

Question 8Cardiac Anatomy and Physiology

The pericardial cavity normally contains a thin film of fluid whose main function is to:

  1. Transmit electrical impulses to the myocardium
  2. Carry nutrients to the endocardium
  3. Reduce friction between the beating heart and surrounding structures Correct answer.
  4. Provide a reservoir of calcium ions

Explanation

Serous pericardial fluid acts as a lubricant, allowing the heart to move with minimal friction inside the pericardial sac. It does not conduct electricity or nourish the inner heart layers.

Question 9Cardiac Anatomy and Physiology

During which phase of the cardiac cycle do the atrioventricular valves close?

  1. Ventricular ejection
  2. Atrial filling
  3. Isovolumetric ventricular relaxation
  4. Isovolumetric ventricular contraction Correct answer.

Explanation

As ventricular pressure rises above atrial pressure at the start of systole, the AV valves snap shut, producing the first heart sound. This occurs before any blood is ejected.

Question 10Cardiac Anatomy and Physiology

The second heart sound (S2) is produced by closure of which valves?

  1. Mitral and tricuspid
  2. Mitral and aortic
  3. Tricuspid and pulmonary
  4. Aortic and pulmonary Correct answer.

Explanation

S2 results from closure of the semilunar valves, the aortic and pulmonary valves, at the end of ventricular ejection. AV valve closure generates the first heart sound.

Question 11Cardiac Anatomy and Physiology

Cardiac output is calculated as:

  1. End-diastolic volume minus end-systolic volume
  2. Heart rate divided by stroke volume
  3. Stroke volume multiplied by heart rate Correct answer.
  4. Mean arterial pressure divided by heart rate

Explanation

Cardiac output equals the volume ejected per beat (stroke volume) times the number of beats per minute (heart rate). The end-diastolic minus end-systolic volume expression defines stroke volume itself.

Question 12Cardiac Anatomy and Physiology

A patient has a stroke volume of 70 mL and a heart rate of 80 beats per minute. What is the cardiac output?

  1. 56 L/min
  2. 5.6 L/min Correct answer.
  3. 8.75 L/min
  4. 0.875 L/min

Explanation

Cardiac output is stroke volume times heart rate: 70 mL × 80 beats/min = 5600 mL/min, or 5.6 L/min. This falls within the normal adult resting range.

Question 13Cardiac Anatomy and Physiology

According to the Frank-Starling relationship, increasing ventricular end-diastolic volume within physiological limits will:

  1. Increase stroke volume Correct answer.
  2. Reverse the direction of blood flow
  3. Decrease stroke volume
  4. Have no effect on stroke volume

Explanation

Greater filling stretches cardiac myocytes, increasing their sensitivity to calcium and the force of contraction, so stroke volume rises. This is the basis of the length-tension relationship in the heart.

Question 14Cardiac Anatomy and Physiology

Which factor most directly increases myocardial oxygen demand?

  1. Decreased heart rate
  2. Decreased contractility
  3. Increased ventricular wall stress Correct answer.
  4. Reduced afterload

Explanation

Myocardial oxygen consumption rises with heart rate, contractility, and wall stress; wall stress depends on pressure and chamber radius. Anything that lowers rate, contractility, or afterload generally reduces demand.

Question 15Cardiac Anatomy and Physiology

The plateau phase of the ventricular myocyte action potential is primarily maintained by:

  1. Calcium influx balanced against potassium efflux Correct answer.
  2. Chloride efflux
  3. Rapid sodium influx
  4. Sodium-potassium pump reversal

Explanation

During phase 2, L-type calcium channels admit calcium while potassium channels allow efflux, producing a prolonged plateau. This plateau extends the refractory period and supports strong contraction.

Question 16Cardiac Anatomy and Physiology

The atrioventricular node introduces a delay in impulse conduction primarily to:

  1. Allow the atria to complete filling of the ventricles Correct answer.
  2. Prevent the SA node from firing
  3. Increase the heart rate
  4. Speed conduction to the Purkinje system

Explanation

The AV nodal delay ensures atrial contraction finishes before ventricular contraction begins, optimizing ventricular filling. It slows rather than accelerates conduction.

Question 17Cardiac Anatomy and Physiology

Which coronary artery most commonly supplies the sinoatrial node in adults?

  1. Right coronary artery Correct answer.
  2. Left main coronary artery
  3. Left circumflex artery
  4. Left anterior descending artery

Explanation

In most people the SA nodal branch arises from the right coronary artery, which also typically supplies the AV node. The left coronary system mainly supplies the anterior and lateral ventricular walls.

Question 18Cardiac Anatomy and Physiology

Aortic valve closure occurs at the boundary between which two phases?

  1. Atrial systole and isovolumetric contraction
  2. Atrial filling and atrial systole
  3. Ventricular ejection and isovolumetric relaxation Correct answer.
  4. Isovolumetric relaxation and atrial filling

Explanation

When ventricular pressure falls below aortic pressure at the end of ejection, the aortic valve closes, marking the start of isovolumetric relaxation. This closure contributes to the second heart sound.

Question 19Cardiac Anatomy and Physiology

Systemic vascular resistance primarily opposes which phase of ventricular activity?

  1. Atrial contraction
  2. Isovolumetric contraction
  3. Ventricular ejection Correct answer.
  4. Diastolic filling

Explanation

Afterload is the resistance the ventricle must overcome to eject blood, so systemic vascular resistance mainly opposes ventricular ejection. Filling is governed by venous return and compliance.

Question 20Cardiac Anatomy and Physiology

The normal direction of blood flow through the heart is best described as:

  1. Right ventricle to right atrium to lungs to left ventricle to left atrium
  2. Right atrium to left atrium to right ventricle to left ventricle
  3. Right atrium to right ventricle to lungs to left atrium to left ventricle Correct answer.
  4. Left atrium to left ventricle to lungs to right atrium to right ventricle

Explanation

Deoxygenated blood enters the right atrium, passes to the right ventricle, goes to the lungs, returns to the left atrium, and is then ejected from the left ventricle. This describes the pulmonary and systemic circuits in series.

Question 21Cardiac Anatomy and Physiology

A patient's stroke volume falls because of reduced contractility. Which compensatory mechanism would most directly help maintain cardiac output?

  1. Reduced venous return
  2. Decreased heart rate
  3. Increased vagal tone
  4. Increased sympathetic stimulation of the heart Correct answer.

Explanation

Sympathetic stimulation raises heart rate and contractility, directly supporting cardiac output when stroke volume is impaired. Vagal tone and reduced venous return would further lower output.

Question 22Cardiac Anatomy and Physiology

Which statement best explains why the heart cannot undergo tetanic contraction under normal conditions?

  1. The absolute refractory period nearly spans the entire action potential Correct answer.
  2. Cardiac myocytes lack actin and myosin
  3. The heart has no sarcoplasmic reticulum
  4. Calcium is never released into the cytosol

Explanation

The long plateau of the cardiac action potential creates a refractory period that lasts almost until relaxation, preventing summation of contractions. This protects the heart's pumping function.

Question 23Cardiac Anatomy and Physiology

In the pressure-volume loop of the left ventricle, an increase in afterload with constant preload primarily causes:

  1. A larger stroke volume
  2. No change in end-systolic volume
  3. A smaller stroke volume and greater end-systolic volume Correct answer.
  4. Increased end-diastolic volume

Explanation

Higher afterload forces the ventricle to shorten less before pressure falls, leaving more residual blood and reducing stroke volume. End-diastolic volume is set by preload, which is held constant.

Question 24Cardiac Anatomy and Physiology

The left anterior descending coronary artery supplies which region of the heart?

  1. Inferior wall of the left ventricle
  2. Right atrium and right ventricle
  3. Anterior wall of the left ventricle and anterior septum Correct answer.
  4. Lateral wall of the left ventricle

Explanation

The LAD runs in the anterior interventricular groove, supplying the anterior left ventricular wall and much of the anterior septum. Occlusion here can impair the main pumping region and conduction pathways.

Question 25Cardiac Anatomy and Physiology

Which combination of changes occurs during normal inspiration and helps increase venous return to the right heart?

  1. Increased intrathoracic pressure and decreased abdominal pressure
  2. Decreased intrathoracic pressure and decreased abdominal pressure
  3. Increased intrathoracic pressure and increased abdominal pressure
  4. Decreased intrathoracic pressure and increased abdominal pressure Correct answer.

Explanation

During inspiration, intrathoracic pressure falls while abdominal pressure rises, drawing blood into the thorax and augmenting right heart filling. This respiratory pump effect varies with breathing.

Question 26Cardiac Anatomy and Physiology

Which chamber of the heart receives oxygenated blood from the pulmonary veins?

  1. Right ventricle
  2. Right atrium
  3. Left atrium Correct answer.
  4. Left ventricle

Explanation

Oxygenated blood returns from the lungs via the pulmonary veins and enters the left atrium. From there it passes through the mitral valve into the left ventricle.

Question 27Cardiac Anatomy and Physiology

Which valve prevents backflow of blood from the left ventricle into the left atrium during ventricular systole?

  1. Pulmonary valve
  2. Mitral valve Correct answer.
  3. Tricuspid valve
  4. Aortic valve

Explanation

The mitral (bicuspid) valve separates the left atrium and left ventricle and closes during ventricular systole to prevent regurgitation. The aortic and pulmonary valves are semilunar valves that prevent backflow from the arteries into the ventricles.

Question 28Cardiac Anatomy and Physiology

Which structure is the normal origin of the electrical impulse that initiates each heartbeat?

  1. Atrioventricular node
  2. Bundle of His
  3. Sinoatrial node Correct answer.
  4. Purkinje fibers

Explanation

The sinoatrial node, located in the upper wall of the right atrium, has the highest rate of spontaneous depolarization and thus acts as the normal pacemaker. The atrioventricular node, bundle of His, and Purkinje fibers are downstream conduction structures.

Question 29Cardiac Anatomy and Physiology

During isovolumetric ventricular contraction, which of the following best describes the state of the valves and ventricular volume?

  1. AV valves are closed and semilunar valves are open, and volume is decreasing
  2. AV valves are open and semilunar valves are closed, and volume is increasing
  3. Both AV and semilunar valves are open, and volume is increasing
  4. Both AV and semilunar valves are closed, and ventricular volume is constant Correct answer.

Explanation

Isovolumetric contraction occurs after the AV valves close and before the semilunar valves open, so all valves are closed and ventricular volume does not change while pressure rises. This phase ends when ventricular pressure exceeds aortic pressure and the aortic valve opens.

Question 30Cardiac Anatomy and Physiology

Which component of the cardiac conduction system is primarily responsible for the rapid, coordinated spread of excitation through the ventricular myocardium?

  1. Sinoatrial node
  2. Purkinje fibers Correct answer.
  3. Internodal pathways
  4. Atrioventricular node

Explanation

Purkinje fibers conduct impulses very rapidly to ventricular muscle, enabling coordinated contraction. The sinoatrial node initiates impulses, the atrioventricular node delays them, and internodal pathways conduct within the atria.

Question 31Cardiac Anatomy and Physiology

Which layer of the heart wall is responsible for generating the force of contraction?

  1. Endocardium
  2. Epicardium
  3. Myocardium Correct answer.
  4. Pericardium

Explanation

The myocardium is the middle layer composed of cardiac muscle cells and is responsible for contraction. The endocardium lines the chambers, the epicardium covers the heart surface, and the pericardium is the surrounding sac.

Question 32Cardiac Anatomy and Physiology

A patient has a heart rate of 50 beats per minute and a stroke volume of 100 mL. What is the cardiac output?

  1. 10.0 L/min
  2. 2.0 L/min
  3. 7.0 L/min
  4. 5.0 L/min Correct answer.

Explanation

Cardiac output is the product of heart rate and stroke volume: 50 beats/min × 100 mL/beat = 5000 mL/min, or 5.0 L/min. This value falls within the normal resting range.

Question 33Cardiac Anatomy and Physiology

Which of the following best describes the role of the atrioventricular valves during ventricular diastole?

  1. They are open, allowing blood to flow from ventricles to atria
  2. They are closed, preventing backflow from ventricles to atria
  3. They are open, allowing blood to flow from atria to ventricles Correct answer.
  4. They are closed, preventing backflow from arteries to ventricles

Explanation

During ventricular diastole, ventricular pressure falls below atrial pressure, causing the AV valves to open and permit ventricular filling. The semilunar valves are closed during most of diastole to prevent arterial backflow.

Question 34Cardiac Anatomy and Physiology

Which of the following is the primary determinant of resting coronary blood flow?

  1. Myocardial oxygen demand Correct answer.
  2. Heart rate alone
  3. Right atrial pressure
  4. Aortic systolic pressure

Explanation

Coronary blood flow is tightly coupled to myocardial oxygen demand, which is met primarily by changes in coronary vascular resistance. Systolic pressure, heart rate, and atrial pressure influence flow but are not the primary determinant.

Question 35Cardiac Anatomy and Physiology

Which of the following changes occurs during normal expiration and affects cardiac function?

  1. Increased heart rate due to vagal withdrawal
  2. Increased intrathoracic pressure Correct answer.
  3. Decreased intrathoracic pressure
  4. Increased venous return to the right heart

Explanation

During expiration, intrathoracic pressure rises toward atmospheric pressure, which reduces venous return to the right heart. Inspiration lowers intrathoracic pressure and increases venous return.

Question 36Cardiac Anatomy and Physiology

Which of the following statements best explains why the left ventricle has a thicker wall than the right ventricle?

  1. The left ventricle receives more coronary blood flow
  2. The left ventricle has a higher heart rate
  3. The left ventricle has a larger chamber volume
  4. The left ventricle pumps against higher resistance Correct answer.

Explanation

The left ventricle must generate higher pressure to overcome systemic vascular resistance, leading to greater wall thickness. The right ventricle pumps against the low resistance of the pulmonary circulation.

Question 37Cardiac Anatomy and Physiology

During the cardiac cycle, which of the following events occurs at the time of the first heart sound (S1)?

  1. Opening of the atrioventricular valves
  2. Opening of the semilunar valves
  3. Closure of the semilunar valves
  4. Closure of the atrioventricular valves Correct answer.

Explanation

S1 is produced by closure of the mitral and tricuspid (AV) valves at the onset of ventricular systole. Semilunar valve closure produces S2, and valve openings are normally silent.

Question 38Cardiac Anatomy and Physiology

Which of the following best describes the function of the chordae tendineae?

  1. They open the atrioventricular valves during diastole
  2. They conduct electrical impulses from the atria to the ventricles
  3. They prevent the atrioventricular valves from prolapsing into the atria during systole Correct answer.
  4. They close the semilunar valves during diastole

Explanation

Chordae tendineae are fibrous cords that attach the AV valve leaflets to papillary muscles and prevent the leaflets from everting into the atria during ventricular systole. They do not open valves or conduct electrical impulses.

Question 39Cardiac Anatomy and Physiology

Which of the following best explains why the heart is able to contract as a functional syncytium?

  1. Cardiac muscle cells are innervated by multiple motor neurons
  2. Cardiac muscle cells have a long refractory period
  3. Cardiac muscle cells are connected by gap junctions at intercalated discs Correct answer.
  4. Cardiac muscle cells lack sarcoplasmic reticulum

Explanation

Gap junctions at intercalated discs allow electrical current to pass freely between cardiac muscle cells, enabling coordinated contraction. This arrangement allows the heart to behave as a syncytium.

Question 40Cardiac Anatomy and Physiology

Which of the following statements best describes the relationship between the pulmonary and systemic circulations?

  1. They are arranged in series and receive equal blood flow Correct answer.
  2. They are arranged in parallel and receive equal blood flow
  3. They are arranged in series and receive unequal blood flow
  4. They are arranged in parallel and receive unequal blood flow

Explanation

The pulmonary and systemic circulations are arranged in series, so the output of the right ventricle equals the output of the left ventricle over time. This ensures that blood flows from the body to the lungs and back to the body.

Question 41Electrocardiography and Rhythm Recognition

On a standard ECG recorded at 25 mm/s, one small square on the horizontal axis represents how much time?

  1. 0.10 seconds
  2. 0.02 seconds
  3. 0.20 seconds
  4. 0.04 seconds Correct answer.

Explanation

At 25 mm/s, 1 mm equals 1/25 second, which is 0.04 s. Each small square is therefore 40 ms, and five small squares (one large square) equal 0.20 s.

Question 42Electrocardiography and Rhythm Recognition

A regular rhythm shows 4 large squares between consecutive R waves. What is the approximate heart rate?

  1. 60 beats/min
  2. 100 beats/min
  3. 50 beats/min
  4. 75 beats/min Correct answer.

Explanation

Using the large-square method, rate equals 300 divided by the number of large squares between R waves. 300/4 = 75 beats/min.

Question 43Electrocardiography and Rhythm Recognition

Which ECG lead is created by placing the exploring electrode on the left leg with the reference formed by the right arm and left arm?

  1. Lead aVF Correct answer.
  2. Lead II
  3. Lead I
  4. Lead aVR

Explanation

Lead aVF uses the left foot as the exploring electrode with the augmented reference from both arms. Lead II also views the left leg but uses the right arm as its reference.

Question 44Electrocardiography and Rhythm Recognition

Which finding defines sinus rhythm on the ECG?

  1. A P wave after every QRS with negative P in lead II
  2. A P wave before every QRS with positive P in lead II Correct answer.
  3. A QRS duration greater than 0.12 seconds
  4. A ventricular rate above 100 beats/min

Explanation

Sinus rhythm requires an upright P wave in lead II (indicating a sinus node origin) with a consistent P-to-QRS relationship. Rate and QRS width are separate descriptors.

Question 45Electrocardiography and Rhythm Recognition

The PR interval is measured from the beginning of the P wave to which point?

  1. The beginning of the QRS complex Correct answer.
  2. The peak of the R wave
  3. The beginning of the T wave
  4. The end of the QRS complex

Explanation

The PR interval spans from the onset of atrial depolarization (start of P) to the onset of ventricular depolarization (start of QRS). It reflects conduction through the atria, AV node, and His-Purkinje system.

Question 46Electrocardiography and Rhythm Recognition

A rhythm is irregularly irregular with no discernible P waves and a narrow QRS. What is the most likely rhythm?

  1. Atrial fibrillation Correct answer.
  2. Second-degree AV block type I
  3. Sinus arrhythmia
  4. Ventricular tachycardia

Explanation

Absent P waves with an irregularly irregular ventricular response is the hallmark of atrial fibrillation. The narrow QRS indicates conduction through the normal His-Purkinje system.

Question 47Electrocardiography and Rhythm Recognition

Which electrode placement is used for lead V1?

  1. Fourth intercostal space at the right sternal border Correct answer.
  2. Fourth intercostal space at the left sternal border
  3. Fifth intercostal space at the midclavicular line
  4. Fifth intercostal space at the anterior axillary line

Explanation

V1 is placed in the fourth intercostal space to the right of the sternum. V2 sits opposite it on the left sternal border.

Question 48Electrocardiography and Rhythm Recognition

What is the normal upper limit for QRS duration in an adult?

  1. 0.20 seconds
  2. 0.12 seconds Correct answer.
  3. 0.08 seconds
  4. 0.10 seconds

Explanation

A normal QRS is generally less than 0.12 s (under 3 small squares). Values of 0.12 s or more suggest a ventricular conduction delay such as bundle branch block.

Question 49Electrocardiography and Rhythm Recognition

A rhythm strip shows a rate of 40 beats/min with upright P waves in lead II, a PR interval of 0.16 s, and a narrow QRS. What is the rhythm?

  1. Sinus bradycardia Correct answer.
  2. Sinus arrest
  3. Complete heart block
  4. Junctional rhythm

Explanation

Upright P waves in lead II with a normal PR and a 1:1 P-QRS relationship indicate sinus origin; a rate under 60 defines bradycardia. The combination is sinus bradycardia.

Question 50Electrocardiography and Rhythm Recognition

A regular narrow-complex tachycardia at 150 beats/min shows a P wave buried in the terminal portion of each QRS. What is the most likely mechanism?

  1. Ventricular tachycardia
  2. Atrial flutter with 2:1 conduction Correct answer.
  3. Sinus tachycardia
  4. Third-degree AV block

Explanation

Atrial flutter typically has an atrial rate near 300 with 2:1 AV conduction producing a ventricular rate near 150. The buried flutter waves are consistent with this.