Quiz on the Cardiovascular System

What is the average weight of the heart?

• 250-350 grams

• 500-600 grams

• 150-200 grams

• 400-450 grams

Answer explanation

The average weight of a human heart typically ranges from 250 to 350 grams, making this the correct choice. Other options exceed or fall below this range.

What is the outer layer of the heart wall called?

• Myocardium

• Endocardium

• Pericardium

• Epicardium

Answer explanation

The outer layer of the heart wall is called the epicardium. It serves as a protective layer and is part of the heart's structure, while the myocardium is the muscle layer and the endocardium lines the heart chambers.

Which chamber of the heart is the thickest?

• Left ventricle

• Right atrium

• Left atrium

• Right ventricle

Answer explanation

The left ventricle is the thickest chamber of the heart because it needs to generate enough pressure to pump oxygenated blood throughout the entire body, unlike the other chambers which pump blood to nearby areas.

What type of valves are the tricuspid and bicuspid valves?

• Atrioventricular valves

• Semilunar valves

• Pulmonary valves

• Coronary valves

Answer explanation

The tricuspid and bicuspid valves are classified as atrioventricular valves because they are located between the atria and ventricles, regulating blood flow within the heart.

Which part of the heart receives deoxygenated blood?

• Left atrium

• Right atrium

• Left ventricle

• Right ventricle

Answer explanation

The right atrium receives deoxygenated blood from the body through the superior and inferior vena cavae, making it the correct answer. The left atrium receives oxygenated blood, while the ventricles pump blood out.

What is the function of the pericardial fluid?

• To provide nutrients to the heart

• To reduce friction between heart layers

• To store blood

• To regulate heart rate

Answer explanation

The pericardial fluid acts as a lubricant, reducing friction between the heart's layers as they contract and relax. This function is crucial for the heart's efficient movement, making 'to reduce friction between heart layers' the correct choice.

What initiates the electrical impulses in the heart?

• Purkinje fibers

• Bundle of His

• Atrioventricular node

• Sinoatrial node

Answer explanation

The sinoatrial node, located in the right atrium, is the primary pacemaker of the heart. It generates electrical impulses that initiate each heartbeat, setting the rhythm for the entire cardiac cycle.

What is the primary role of the myocardium?

• To store oxygen

• To conduct electrical impulses

• To pump blood

• To protect the heart

Answer explanation

The primary role of the myocardium is to pump blood throughout the body. It is the muscular layer of the heart that contracts to facilitate blood circulation, making 'to pump blood' the correct answer.

Which of the following is NOT a part of the intrinsic conduction system?

• Bundle of His

• Coronary sinus

• Sinoatrial node

• Atrioventricular node

Answer explanation

The intrinsic conduction system includes the sinoatrial node, atrioventricular node, and Bundle of His, which are responsible for heart rhythm. The coronary sinus, however, is a vessel that drains blood, not part of the conduction system.

What does the QRS complex in an ECG represent?

• Ventricular depolarization

• Ventricular repolarization

• Atrial depolarization

• Atrial repolarization

Answer explanation

The QRS complex in an ECG represents ventricular depolarization, which is the electrical activity that triggers the ventricles to contract. This is crucial for pumping blood to the lungs and the rest of the body.