36 Questions
What is the role of Ca++ channels at 0mV during repolarization?
They close
Which component of the heart's conduction system would fire the slowest times per minute?
Purkinje fibers
What would be the heart rate range if the AV node was the primary pacemaker without endocrine control?
40 - 60 BPM
How many leads are typically used for recording an ECG or EKG?
12 leads
What happens to K+ channels at 0mV during typical repolarization?
They open
What is the main function of P wave in an ECG?
Depolarization of the atria
Which phase of the cardiac cycle is characterized by the pumping of blood into circulation?
Ventricular systole
What is the primary function of an artificial pacemaker in the context of heart function?
Delivers electrical impulses for effective heart contractions
During which phase of the cardiac cycle does the end systolic volume (ESV) refer to the amount of blood left in the ventricles after stroke volume is pushed out?
Ventricular diastole
What is the significance of the T wave in an ECG?
Repolarization of the ventricles
What is the primary purpose of an Automatic External Defibrillator (AED)?
Corrects fibrillations
Where is the heart located in the body?
Between the lungs in the mediastinum
Which chamber of the heart is responsible for pumping blood out to the body or lungs?
Ventricles
Which layer of the heart is most superficial?
Epicardium
What is the function of auricles in the heart?
Collecting and holding blood to empty into the atria
Which structure separates the parietal and visceral layers of the serous pericardium?
Pericardial Cavity
What is the size of a typical heart compared to that of an athlete's heart?
Athlete's heart is larger
Which type of cells in the heart initiate an electrical potential at a fixed rate?
Autorhythmic cells
What is the purpose of the desmosomes in cardiac muscle cells?
Stop cells from ripping apart
Why do semilunar valves make an audible sound as they close?
They have no muscular attachments
What is the main function of the Purkinje fibers in the heart?
Spread the impulse around the ventricles
Which structure divides the heart into chambers and are physical extensions of myocardium?
Septum
What happens when cardiac conductive cells plateau during depolarization?
Ca++ channels open
What is the role of endothelins released by the endothelium in the heart?
Regulate growth patterns of cardiac muscle cells
How do tricuspid and mitral valves close in the heart?
Due to papillary muscles
What is the primary function of coronary veins in the circulatory system?
Return deoxygenated blood back to the right atrium
Which heart sound is associated with the closing of the semilunar valves?
S2
What is the normal range for Cardiac Output (CO) in liters per minute?
4 - 8 L/min
What is the formula to calculate Cardiac Output (CO)?
CO = HR * SV
Which factor increases Heart Rate (HR) through sympathetic stimulation?
Norepinephrine release
What is the percentage range for a normal Ejection Fraction?
50% - 70%
Which reflex is triggered by increased blood in the atria resulting in a sympathetic response to increase heart rate?
Atrial reflex
How can caffeine and nicotine affect Heart Rate?
Increase it
Which electrolyte alteration can decrease Heart Rate?
Alkalosis (too few hydrogen ions)
What happens if there is little time for blood to fill during increased Heart Rate?
(ESV) End-Systolic Volume decreases
Which event occurs before other heart sounds when blood is being pushed into a stiff ventricle?
S4 sound
Test your knowledge on the processes involved in cardiac muscle contraction and conduction, including ion channels, refractory periods, and the role of calcium ions. Explore topics such as SA node firing rate, AV node function, and the atrioventricular bundle. Challenge yourself with questions on troponin, myosin-actin cross bridge formation, and endocrine control of heart rate.
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