#1
Which of the following structures is responsible for generating the electrical impulses in the heart?
Sinoatrial node
ExplanationThe Sinoatrial node initiates the heart's electrical activity.
#2
During which phase of the cardiac cycle does ventricular filling occur?
Ventricular diastole
ExplanationVentricular filling occurs during Ventricular diastole.
#3
What is the name of the condition characterized by an abnormal heart rhythm due to rapid, irregular electrical impulses in the atria?
Atrial fibrillation
ExplanationAtrial fibrillation is characterized by irregular electrical impulses in the atria.
#4
What is the primary function of the pericardium?
To prevent overfilling of the heart
ExplanationThe pericardium prevents overfilling of the heart.
#5
What is the term for the amount of blood in the ventricles at the end of diastole, just before systole begins?
End-diastolic volume
ExplanationEnd-diastolic volume is the blood volume in ventricles before systole.
#6
What is the term for the abnormal heart sound caused by turbulent blood flow, typically due to a defective heart valve?
Murmur
ExplanationA murmur is caused by turbulent blood flow due to a defective heart valve.
#7
Which of the following conditions is characterized by the deposition of fatty plaques in the coronary arteries?
Atherosclerosis
ExplanationAtherosclerosis involves fatty plaque buildup in coronary arteries.
#8
What is the primary function of the atrioventricular (AV) node in the heart?
To conduct electrical impulses to the ventricles
ExplanationThe AV node conducts electrical impulses to the ventricles.
#9
What is the term for the volume of blood ejected by the left ventricle in one contraction?
Stroke volume
ExplanationStroke volume is the volume of blood ejected by the left ventricle in one contraction.
#10
Which of the following ions plays a crucial role in the initiation and propagation of action potentials in cardiac muscle cells?
Calcium (Ca2+)
ExplanationCalcium ions play a crucial role in initiating and propagating action potentials in cardiac muscle cells.
#11
Which of the following statements about the Frank-Starling mechanism is true?
It states that increased preload leads to increased stroke volume.
ExplanationThe Frank-Starling mechanism states increased preload leads to increased stroke volume.
#12
Which of the following vessels supplies oxygenated blood to the myocardium itself?
Coronary arteries
ExplanationCoronary arteries supply oxygenated blood to the myocardium.
#13
Which of the following hormones is primarily responsible for increasing heart rate and contractility during 'fight or flight' responses?
Epinephrine
ExplanationEpinephrine increases heart rate and contractility in 'fight or flight' responses.
#14
What is the term for the period of time during which a myocardial cell is unable to respond to a new stimulus, regardless of stimulus strength?
Refractory period
ExplanationThe refractory period is when a myocardial cell cannot respond to a new stimulus.
#15
Which of the following factors is NOT a determinant of cardiac output?
Blood viscosity
ExplanationBlood viscosity is not a determinant of cardiac output.
#16
Which of the following is a characteristic feature of diastolic heart failure?
Impaired ventricular relaxation
ExplanationDiastolic heart failure is characterized by impaired ventricular relaxation.
#17
What is the term for the condition characterized by an accumulation of fluid in the pericardial sac, compressing the heart and impairing its function?
Cardiac tamponade
ExplanationCardiac tamponade is the accumulation of fluid in the pericardial sac.
#18
Which of the following conditions is characterized by a rapid, uncoordinated contraction of the ventricles, leading to inefficient pumping of blood?
Ventricular fibrillation
ExplanationVentricular fibrillation involves rapid, uncoordinated ventricular contractions.