#1
Which of the following is the primary pacemaker of the heart?
Sinoatrial (SA) node
ExplanationInitiates electrical impulses for heart contraction.
#2
What is the term for the relaxation phase of the cardiac cycle?
Diastole
ExplanationHeart muscle relaxation allowing chambers to fill with blood.
#3
Which type of blood vessel carries oxygenated blood away from the heart?
Artery
ExplanationBlood vessel transporting oxygenated blood from the heart.
#4
Which of the following is NOT a component of the intrinsic conduction system of the heart?
Purkinje fibers
ExplanationPurkinje fibers are part of the conduction system.
#5
What is the primary function of the coronary arteries?
Supply oxygen and nutrients to the heart muscle
ExplanationBlood vessels providing nutrients and oxygen to the heart.
#6
What is the primary function of the atrioventricular (AV) valves in the heart?
Prevent backflow of blood into the atria
ExplanationValves ensuring blood flows in one direction.
#7
Which hormone is released during stress and increases heart rate and blood pressure?
Cortisol
ExplanationStress hormone affecting cardiovascular function.
#8
What is the Frank-Starling law of the heart related to?
Preload and stroke volume
ExplanationHeart's ability to adjust output based on venous return.
#9
What is the term for the volume of blood ejected by the left ventricle in one minute?
Cardiac output
ExplanationTotal blood pumped by the heart per minute.
#10
Which neurotransmitter is released by the vagus nerve to decrease heart rate?
Acetylcholine
ExplanationNeurotransmitter inhibiting heart rate via the vagus nerve.
#11
Which of the following is a function of the pericardium?
Protection of the heart
ExplanationProtective sac surrounding and supporting the heart.
#12
What is the primary purpose of the mitral valve (bicuspid valve) in the heart?
Prevent backflow of blood into the left atrium
ExplanationEnsures one-way flow from the left atrium to the left ventricle.
#13
Which ion is primarily responsible for the depolarization phase in cardiac muscle cells?
Sodium (Na+)
ExplanationKey ion for initiating electrical signals in the heart.
#14
What is the term for the part of the electrocardiogram (ECG) that represents ventricular depolarization?
QRS complex
ExplanationECG segment indicating ventricular contraction initiation.
#15
What is the primary function of the atrioventricular (AV) node in the heart?
Filter and delay electrical signals
ExplanationDelays electrical impulses for proper atrial-ventricular coordination.
#16
Which factor primarily determines preload in the heart?
End-diastolic volume
ExplanationVolume of blood in the ventricle before contraction.
#17
In the context of cardiac physiology, what does the term 'afterload' refer to?
Force opposing ventricular ejection
ExplanationResistance ventricle faces during blood ejection.
#18
Which electrolyte imbalance can potentially lead to cardiac arrhythmias?
Hyperkalemia
ExplanationExcessive potassium levels affecting heart rhythm.