#1
Which of the following is true regarding the sinoatrial (SA) node?
It initiates the electrical impulse for cardiac contraction
ExplanationSA node starts heart's electrical impulse.
#2
What is the normal resting heart rate for an adult?
60-80 beats per minute
ExplanationNormal adult heart rate range: 60-80 bpm.
#3
Which of the following is not a risk factor for developing cardiovascular disease?
Regular exercise
ExplanationRegular exercise reduces cardiovascular disease risk.
#4
Which of the following represents the correct sequence of events during the cardiac cycle?
Ventricular systole → Atrial systole → Ventricular diastole
ExplanationCardiac cycle: ventricular systole → atrial systole → ventricular diastole.
#5
Which of the following statements about the cardiac conduction system is correct?
The bundle of His conducts the electrical signal from the atria to the ventricles.
ExplanationBundle of His carries signal from atria to ventricles.
#6
What is the correct sequence of cardiac electrical conduction through the heart?
SA node → AV node → Bundle of His → Purkinje fibers
ExplanationSA → AV → Bundle of His → Purkinje fibers conduction.
#7
What does the P wave represent in an electrocardiogram (ECG)?
Atrial depolarization
ExplanationP wave indicates atrial depolarization.
#8
Which of the following conditions is characterized by an abnormal rhythm of the heart?
Arrhythmia
ExplanationArrhythmia denotes abnormal heart rhythm.
#9
Which of the following ions is primarily responsible for the depolarization phase of cardiac muscle cells?
Sodium (Na+)
ExplanationSodium ions drive cardiac cell depolarization.
#10
What is the primary function of the atrioventricular (AV) node in the heart's conduction system?
To delay the impulse before transmitting it to the ventricles
ExplanationAV node delays impulse for ventricular filling.
#11
Which wave on an ECG represents ventricular depolarization?
QRS complex
ExplanationQRS complex signifies ventricular depolarization.
#12
What is the term for the period of time during which the heart is contracting and pumping blood?
Systole
ExplanationSystole: heart contraction and blood ejection phase.
#13
Which of the following is responsible for initiating the contraction of the ventricles?
Purkinje fibers
ExplanationPurkinje fibers trigger ventricular contraction.
#14
What is the term for the volume of blood pumped out by each ventricle with each heartbeat?
Stroke volume
ExplanationStroke volume: blood ejected by each ventricle per beat.
#15
Which of the following factors does NOT affect cardiac output?
Blood viscosity
ExplanationBlood viscosity doesn't affect cardiac output.
#16
During which phase of the cardiac cycle does blood flow from the atria to the ventricles?
Atrial diastole
ExplanationAtrial diastole: blood flows from atria to ventricles.
#17
What does the ST segment represent on an ECG?
Ventricular repolarization
ExplanationST segment indicates ventricular repolarization.
#18
What is the primary function of the bundle of His?
To transmit the electrical impulse rapidly from the AV node to the ventricles.
ExplanationBundle of His fast-tracks AV node signal to ventricles.
#19
What is the term for the phase of the cardiac cycle during which the ventricles are relaxed and filling with blood?
Diastole
ExplanationDiastole: ventricles relax and fill with blood.
#20
Which of the following factors can cause an increase in heart rate?
Increased levels of potassium ions
ExplanationHigh potassium levels can raise heart rate.
#21
What is the term for the time between ventricular depolarization and repolarization on an ECG?
QT interval
ExplanationQT interval covers ventricular electrical activity.
#22
What does the QT interval represent on an ECG?
The time between ventricular repolarization and the next depolarization
ExplanationQT interval: ventricular repolarization to next depolarization.
#23
Which of the following is a characteristic feature of atrial fibrillation on an ECG?
Absence of P waves
ExplanationAtrial fibrillation shows no P waves on ECG.
#24
Which of the following conditions is characterized by a rapid and irregular heartbeat originating in the atria?
Atrial fibrillation
ExplanationAtrial fibrillation: rapid, irregular atrial heartbeat.
#25
What is the term for the amount of blood ejected by the ventricles in one minute?
Cardiac output
ExplanationCardiac output: blood ejected by ventricles per minute.