Cardiac Conduction System and Electrocardiogram Quiz

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What happens at 0mV in terms of ion channels during repolarization of the heart?

Ca++ channels open and K+ channels close

Ca++ and K+ channels both open

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

Ca++ and K+ channels both close

What is the function of Ca++ ions binding to troponin during muscle contraction?

Ca++ ions inhibit myosin and actin cross bridge formation

Ca++ ions regulate heart rate

Ca++ ions prevent muscle contraction

Ca++ ions allow the myosin and actin cross bridge formation (correct)

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

Between 80 - 100 times (correct)

Less than 30 times

Between 40 - 60 times

Between 30 - 40 times

What is the purpose of an Electrocardiogram (ECG or EKG)?

To record electrical signals of the heart Signup and view all the answers

Which part of the heart has the lowest firing rate recorded?

Purkinje fibers Signup and view all the answers

What is the primary function of the P wave in the cardiac cycle?

Depolarization of the atria Signup and view all the answers

Which phase occurs when the semilunar valves are closed and blood flows into the atria and through into the ventricles?

Atrial diastole Signup and view all the answers

What is the primary function of an artificial pacemaker in cardiac muscle metabolism?

Ensuring effective heart contractions Signup and view all the answers

During ventricular diastole, what happens to the semilunar valves?

They close as relaxation phase begins Signup and view all the answers

Which phase in the cardiac cycle involves an increase in pressure that forces the semilunar valves to open?

Ventricular systole Signup and view all the answers

What is the main purpose of the QRS complex in the cardiac cycle?

Depolarization of ventricles and masking repolarization of atria Signup and view all the answers

Where is the heart located in the body?

Between the lungs in the mediastinum Signup and view all the answers

What is the function of the ventricles in the heart?

Pump blood out to the body or lungs Signup and view all the answers

Which chamber of the heart connects to the pulmonary trunk?

Right ventricle Signup and view all the answers

What is the purpose of the auricles in the heart?

Hold blood and empty into atria Signup and view all the answers

Which blood vessel is the only artery to carry deoxygenated blood?

Pulmonary artery Signup and view all the answers

What is the middle thickest layer of the heart that contains muscle cells, nerve fibers, and blood vessels?

Myocardium Signup and view all the answers

What are the audible sounds of a healthy heart?

S1 and S2 Signup and view all the answers

Which condition is referred to as S7?

Having both S3 and S4 Signup and view all the answers

What is the formula for calculating Cardiac Output (CO)?

CO = SV * HR Signup and view all the answers

What is considered a normal range for Cardiac Output (CO) in liters per minute?

4 - 8 L/min Signup and view all the answers

What is the percentage range for a normal Ejection Fraction?

50% - 70% Signup and view all the answers

Where does nervous control of Heart Rate come from?

Medulla oblongata Signup and view all the answers

Which stimulation dominates the autonomic tone of the heart?

Vagal stimulation Signup and view all the answers

What happens to Stroke Volume (SV) if there is less filling time?

Decreases SV Signup and view all the answers

'Cardiac reserve' refers to:

The difference between max CO and resting CO Signup and view all the answers

What increases the ventricular stretch leading to more powerful contraction of sarcomeres?

Increased filling time Signup and view all the answers

Which layer of the heart is described as the innermost layer that lines the chambers and covers heart valves?

Endocardium Signup and view all the answers

What cells release endothelins, strong vasoconstrictors that may regulate growth patterns of cardiac muscle cells?

Endothelial cells Signup and view all the answers

Which structure in the heart divides it into chambers and is described as physical extensions of the myocardium?

Septum Signup and view all the answers

What is the function of the moderator band in the right ventricle of the heart?

To conduct cardiac impulses Signup and view all the answers

Which valve disorder is usually caused by inflammation?

Endocarditis Signup and view all the answers

What is the function of coronary arteries in the heart?

Bring oxygenated blood to the myocardium Signup and view all the answers

What is the role of gap junctions in cardiac muscle cells?

Allow ions to travel between cells for proper contractile rhythm Signup and view all the answers

Where is the Sinoatrial (SA) node located in the heart, and what is its function?

In the right atrium, sets normal cardiac rhythm Signup and view all the answers