Cardiac Conduction System and Action Potential Quiz

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What happens at 0mV in terms of ion channels?

Ca++ channels open and K+ channels close

Both Ca++ and K+ channels open

Ca++ channels close and K+ channels open (correct)

Both Ca++ and K+ channels close

Which ion binds to troponin to allow the myosin and actin cross bridge?

Ca++ (correct)

Na+

Cl-

K+

If not for endocrine control, how many times per minute would the SA node fire?

30 - 40 times

40 - 60 times

15 - 20 times

80 - 100 times (correct)

Which part of the heart has been recorded with the lowest heart rate of 28 BPM?

Purkinje fibers Signup and view all the answers

What abbreviations are commonly used to refer to the recording of electrical signals of the heart?

ECG or EKG Signup and view all the answers

Where is the heart located?

In a space called the mediastinum Signup and view all the answers

What structures attach at the base of the heart?

Superior and inferior vena cava, aorta, and pulmonary trunk Signup and view all the answers

Which chamber of the heart collects blood and pushes it into the lower chambers?

Atria Signup and view all the answers

What type of blood does the pulmonary artery carry?

Deoxygenated blood Signup and view all the answers

Which layer of the heart is described as the middle thickest layer, containing muscle cells, nerve fibers, and blood vessels?

Myocardium Signup and view all the answers

What structure produces lubricating fluid in the pericardial cavity?

Visceral layer Signup and view all the answers

During the cardiac cycle, what process occurs when the ventricles are relaxed and filling with blood?

Atrial diastole Signup and view all the answers

Which part of the heart's electrical conduction system is responsible for depolarization of the ventricles and masks atrial repolarization?

QRS complex Signup and view all the answers

What is the primary function of artificial pacemakers in the context of cardiac muscle physiology?

Correcting fibrillations Signup and view all the answers

Which phase of the cardiac cycle involves the atria contracting after depolarization, known as 'atrial kick'?

Atrial systole Signup and view all the answers

What term describes the amount of blood remaining in the ventricles after the stroke volume has been pushed out during ventricular systole?

End systolic volume (ESV) Signup and view all the answers

Which part of the cardiac cycle marks the relaxation phase when the semilunar valves close, and both the atrioventricular valves and semilunar valves are shut?

Ventricular diastole Signup and view all the answers

What is the function of the endothelium in the heart?

Lines the chambers filled with blood Signup and view all the answers

Which type of muscle cells make up 99% of the cardiac muscle and are responsible for pumping blood through the body?

Myocardial contractile cells Signup and view all the answers

Which chamber in the heart receives oxygenated blood from the pulmonary veins?

Left atrium Signup and view all the answers

What is the primary function of the atrioventricular (AV) node in the heart's conduction system?

Slows down impulses Signup and view all the answers

Which valve disorder is usually caused by inflammation in the heart?

Mitral valve stenosis Signup and view all the answers

What is the primary role of the semilunar valves in the heart?

Ensure unidirectional blood flow Signup and view all the answers

Which structure divides the heart into chambers and has physical extensions of myocardium?

Septum Signup and view all the answers

In cardiac muscle cells, what is the function of desmosomes located at intercalated discs?

Prevent muscle cells from ripping apart Signup and view all the answers

Which statement accurately describes Purkinje fibers in the heart's conduction system?

Branch into right and left bundle branches after receiving impulses from AV node Signup and view all the answers

What is the role of coronary circulation in the heart?

Bringing blood to myocardium and other components Signup and view all the answers

What is the function of the atrioventricular valves?

Closing to prevent backflow of blood into the atria during ventricular contraction Signup and view all the answers