40 Questions
What is the heart sound associated with the closure of aortic and pulmonary valves known as?
S2
Which condition is characterized by uncoordinated atrial and ventricular contractions due to a defect in the conduction system?
Atrial fibrillation
Which component of the electrocardiogram is the result of ventricular depolarization and precedes ventricular contraction?
QRS complex
What can happen in ventricular fibrillation that makes it more life-threatening?
Ventricles pump without filling
What is the purpose of defibrillation?
To shock the heart back into a normal rhythm
During depolarization in the heart, the potential moves ________.
from RMP to less negative values
Which node in the heart acts as the pacemaker and controls the electrical impulses for contraction?
Sinoatrial node (SA)
What is the main function of diastole in the cardiac cycle?
Filling the chambers with blood
At the beginning of the cardiac cycle, what happens to the atrioventricular (AV) valves?
They open
What occurs during systole in the cardiac cycle?
Expulsion of blood from the heart
What is the correct sequence of electrical impulse propagation through the heart?
SA node → atria → AV node → Bundle of His → AV bundle branches → Purkinje fibres → ventricles
What is the approximate time taken for the electrical impulses to travel from the SA node to the Purkinje fibres?
220 milliseconds
Which event on the electrocardiogram (ECG) represents ventricular depolarization?
QRS complex
What is the heart sound associated with the closure of the atrioventricular (AV) valves during ventricular systole?
S1 or 'lub'
Which part of the electrocardiogram (ECG) represents ventricular repolarization?
T wave
What initiates atrial systole in the heart?
SA node excitation leading to atrial depolarization
Which part of the heart experiences depolarization indicated by the P wave on an ECG?
Atrial walls
What is the purpose of the delay at the AV node for approximately 0.1 second?
To ensure full contraction of the atria for complete emptying
Where are the AV bundle branches located in the heart?
Within the septum of the heart
What follows the excitation of the SA node in the heart's electrical conduction system?
Depolarization of atrial walls
What is the normal cardiac output in liters per minute in a healthy individual?
5.25 L/min
What is the term used to describe abnormal heart sounds?
Heart murmurs
What causes a high pitched sound or a click to be heard in the case of a stenotic valve?
Narrowed valve
Which factor maintains cardiac output when stroke volume declines due to factors like decreased blood volume or weakened heart?
Increased heart rate
What is the main factor determining stroke volume in the heart's pumping cycle?
End diastolic volume (EDV)
What part of the nervous system increases heart rate?
Autonomic nervous system
Which of the following describes preload in relation to the cardiac muscle cells?
The degree to which the cardiac muscle cells are stretched before contraction
What effect does anything that increases end-diastolic volume (EDV) have on stroke volume (SV)?
Increases SV
Which of the following is considered an extrinsic control of stroke volume?
Thyroid hormones increasing force of contraction
Which technique can be used to measure ejection fraction in cardiac function evaluation?
Echocardiography
What is the primary function of arterioles?
To regulate blood flow to capillaries through vasodilation and vasoconstriction
What is the primary factor that determines the magnitude of the pulse pressure?
Stroke volume and speed of ejection
Which of the following statements about arterial compliance is true?
Venous compliance is approximately 30 times larger than arterial compliance
What is the primary function of arteries?
To act as pressure reservoirs due to their elastic recoil
What is the purpose of the radio-opaque contrast material injected during cardiac catheterization?
To evaluate cardiac function and identify narrowed coronary arteries
Which of the following structures is responsible for the exchange of gases and nutrients between blood and tissues?
Capillaries
What is the effect of a decrease in arterial compliance?
Increased pulse pressure
Which of the following structures is part of the vascular system?
Venules
What is the difference between systolic and diastolic pressure called?
Pulse pressure
Which of the following statements about the vascular system is true?
The amount of vascular smooth muscle cells and endothelial cells varies between arteries and veins
This quiz covers terminology related to action potentials and graded potentials in the context of the circulatory system, including depolarization, repolarization, and hyperpolarization. It also includes information about heartbeat coordination and the node C.
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