31 Questions
What is the role of Ca++ channels at 0mV during repolarization?
Closing to prevent premature contractions
Which heart node would fire 80 - 100 times per minute without endocrine control?
SA node
What is the function of slow Ca++ channels in the heart?
Allowing for the plateau phase
Which part of the heart has the lowest firing rate among the listed nodes and fibers?
Purkinje fibers
What is the primary purpose of an Electrocardiogram (ECG or EKG)?
To record electrical signals of the heart
Which layer of the heart is the most superficial?
Epicardium
What is the purpose of the auricles in the heart?
To hold blood and empty into atria
Which chamber of the heart connects to the pulmonary trunk?
Right ventricle
Where is the heart located in the body?
Between the lungs in the mediastinum
How many chambers does a typical heart have?
4
What separates the heart from other structures within the chest?
Pericardium
During which phase of the cardiac cycle does the P wave represent the depolarization of the atria?
Atrial systole
What is the function of an artificial pacemaker in relation to heart contractions?
Delivers electrical impulses for effective heart contractions
Which phase of the cardiac cycle is characterized by ventricular relaxation and semilunar valves closing?
Ventricular diastole
What is the main purpose of an AED (Automated External Defibrillator)?
Correct fibrillations
Which phase of the cardiac cycle involves the pumping of blood into circulation?
Atrial systole
What is the average amount of blood pushed out by the ventricles in each heartbeat called?
'Stroke volume'
Which event in the cardiac cycle is associated with the first heart sound, S1?
Closing of the atrioventricular valves
What condition might be present if both the S3 and S4 heart sounds are heard together?
S7
What calculation is used to determine the cardiac output (CO)?
CO = SV * HR
What is the normal range for ejection fraction (EF) in cardiac physiology?
50% - 70%
During exercise, how does an increase in heart rate (HR) affect cardiac output (CO)?
Increases CO
What is the target heart rate used to maintain high cardiac output during physical activity based on?
% of maximum heart rate
Which layer of the heart releases endothelins that act as strong vasoconstrictors?
Endocardium
What is the role of the Fossa ovalis in the heart?
Was a foramen ovale while a fetus
Which chamber of the heart receives deoxygenated blood from systemic circulation?
Right atrium
What is the function of the moderator band in the heart?
Assists in closing the tricuspid valve
Why do semilunar valves produce an audible sound as they close?
Due to having no muscular attachments
What is the purpose of anastomosis in coronary circulation?
To connect blood vessels and allow alternative flow paths
Which type of cardiac muscle cells are responsible for initiating and propagating action potentials?
Myocardial conducting cells
Where is the SA node located in the heart?
Right atrium
Test your knowledge of the cardiac conduction system and action potentials with this quiz. Explore topics such as calcium channels, refractory periods, SA node firing rates, and more.
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