The pericardial cavity contains serous fluid that reduces friction as the heart beats.
Correct Answer
True
True. The thin film of serous fluid between the parietal and visceral layers of the serous pericardium lets the heart move with little friction. Too much fluid in this space can compress the heart.
Category: Heart Anatomy
Question 2
The superior and inferior venae cavae return deoxygenated blood to the left atrium.
Correct Answer
False
False. The venae cavae empty deoxygenated systemic blood into the right atrium. The left atrium receives oxygenated blood from the pulmonary veins.
Category: Heart Anatomy
Question 3
The interventricular septum separates the right ventricle from the left ventricle.
Correct Answer
True
True. The thick interventricular septum divides the two ventricles so oxygenated and deoxygenated blood do not mix. The thinner interatrial septum separates the two atria.
Category: Heart Anatomy
Question 4
Pulmonary veins carry deoxygenated blood from the lungs to the heart.
Correct Answer
False
False. Pulmonary veins carry freshly oxygenated blood from the lungs to the left atrium. They are veins because they carry blood toward the heart, not because of their oxygen content.
Category: Heart Anatomy
Question 5
Cardiac muscle cells are branched and striated.
Correct Answer
True
True. Cardiac muscle cells are short, branched and striated, with sarcomeres arranged much like those of skeletal muscle. Their branches connect to neighboring cells at intercalated discs.
Category: Cardiac Muscle
Question 6
Gap junctions in intercalated discs block the movement of ions between neighboring cardiac muscle cells.
Correct Answer
False
False. Gap junctions allow ions to pass directly from one cardiac cell to the next. This lets action potentials spread rapidly so the cells contract as a coordinated unit.
Category: Cardiac Muscle
Question 7
Cardiac muscle depends mainly on aerobic metabolism and contains large numbers of mitochondria.
Correct Answer
True
True. Because the heart never rests, its muscle relies on a steady supply of oxygen and has abundant mitochondria and myoglobin. This is why reduced coronary blood flow quickly damages the myocardium.
Category: Cardiac Muscle
Question 8
The SA node is located in the wall of the left ventricle.
Correct Answer
False
False. The SA node lies in the upper wall of the right atrium near the opening of the superior vena cava. From there its impulses spread across the atria to the AV node.
Category: Conduction System
Question 9
Purkinje fibers spread the impulse through the ventricles so that contraction begins at the apex and moves toward the base.
Correct Answer
True
True. Purkinje fibers carry the impulse rapidly to the ventricular muscle starting near the apex. Contracting from the bottom upward squeezes blood toward the arteries at the base of the heart.
Category: Conduction System
Question 10
On a normal ECG, atrial repolarization is hidden by the QRS complex.
Correct Answer
True
True. Atrial repolarization occurs at the same time as ventricular depolarization. The much larger QRS complex masks it, so it does not appear as a separate wave.
Category: Conduction System
Question 11
The T wave of an ECG represents atrial depolarization.
Correct Answer
False
False. The T wave represents ventricular repolarization. Atrial depolarization is shown by the P wave.
Category: Conduction System
Question 12
The second heart sound is caused by closure of the semilunar valves.
Correct Answer
True
True. The second heart sound, the dub, occurs at the start of ventricular diastole when the aortic and pulmonary valves close. It marks the end of ventricular ejection.
Category: Cardiac Cycle
Question 13
During ventricular ejection, the atrioventricular valves are open and the semilunar valves are closed.
Correct Answer
False
False. During ejection the semilunar valves are open so blood can leave the ventricles, and the AV valves are closed to prevent backflow into the atria.
Category: Cardiac Cycle
Question 14
Contraction of the atria provides most of the blood that fills the ventricles.
Correct Answer
False
False. Most ventricular filling is passive and occurs while the atria and ventricles are both relaxed. Atrial contraction adds only the final, smaller portion.
Category: Cardiac Cycle
Question 15
Cardiac output is calculated by dividing stroke volume by heart rate.
Correct Answer
False
False. Cardiac output equals stroke volume multiplied by heart rate. It is the volume of blood one ventricle pumps each minute.
Category: Cardiac Physiology
Question 16
Ejection fraction is the percentage of end-diastolic volume that a ventricle ejects in one beat.
Correct Answer
True
True. Ejection fraction is stroke volume divided by end-diastolic volume, expressed as a percentage. A low ejection fraction is a sign of a weakened ventricle, as in many cases of heart failure.
Category: Cardiac Physiology
Question 17
Sympathetic stimulation of the heart decreases heart rate and the force of contraction.
Correct Answer
False
False. Sympathetic stimulation, through norepinephrine, increases both heart rate and the force of contraction. Parasympathetic stimulation is what slows the heart rate.
Category: Cardiac Physiology
Question 18
An adult resting heart rate below 60 beats per minute is called bradycardia.
Correct Answer
True
True. Bradycardia means a resting heart rate below 60 beats per minute. It can be normal in well-trained athletes but may also signal a conduction problem.
Category: Cardiac Physiology
Question 19
In the embryo, the primitive ventricle develops into the right ventricle.
Correct Answer
False
False. The primitive ventricle develops into the left ventricle. The right ventricle forms from the bulbus cordis.
Category: Heart Development
Question 20
In the fetal heart, the foramen ovale allows blood to pass from the right atrium to the left atrium.
Correct Answer
True
True. The foramen ovale lets much of the blood entering the right atrium bypass the fetal lungs by flowing into the left atrium. After birth it closes, leaving the fossa ovalis.
Category: Heart Development