Cardiac Muscle Contraction and Electrical Conduction Quiz

What is the role of the atria in the heart?

Push blood into the ventricles (correct)
Collect deoxygenated blood and pump it out to the body or lungs
Collect oxygenated blood and pump it out to the body or lungs
Produce lubricating fluid for the pericardial cavity

Which chamber of the heart is responsible for pumping blood out to the body or lungs?

Left atrium
Right ventricle
Left ventricle (correct)
Right atrium

What separates the two layers of the serous pericardium in the heart?

Myocardium
Pericardial cavity (correct)
Lubricating fluid
Fat-filled grooves

Which structure of the heart produces fluid that lubricates the pericardial cavity?

Epicardium (C) Signup and view all the answers

In which circuit does the right ventricle of the heart connect to the pulmonary trunk?

Pulmonary circuit (C) Signup and view all the answers

What is the main function of the myocardium in the heart?

Contain muscle cells, nerve fibers, and blood vessels (C) Signup and view all the answers

What happens at 0mV during repolarization of the heart?

Ca++ channels close and K+ channels open (B) Signup and view all the answers

What role do Ca++ ions play in the process of muscle contraction?

Ca++ binds to troponin to enable myosin and actin cross-bridge formation (D) Signup and view all the answers

Which component of the heart's conduction system has the fastest intrinsic firing rate?

SA node (B) Signup and view all the answers

What is the purpose of placing electrodes on the body in an ECG?

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

In an ECG, what does a longer QT interval indicate?

Increased risk of arrhythmias (D) Signup and view all the answers

What is the main purpose of AED's?

To correct fibrillations (A) Signup and view all the answers

During which phase of the cardiac cycle does systole occur?

During ventricular systole (C) Signup and view all the answers

What is the function of myoglobin in heart cells?

To store oxygen in muscle cells (B) Signup and view all the answers

What happens during the T wave in the heart's electrical activity?

Repolarization of the ventricles (C) Signup and view all the answers

What occurs during atrial systole in the cardiac cycle?

Atrial contraction following depolarization (D) Signup and view all the answers

What is the significance of end systolic volume (ESV) in the cardiac cycle?

Amount of blood left in ventricles after stroke volume is pushed out (D) Signup and view all the answers

Which heart sound is produced by the closing of the atrioventricular valves?

S1 (B) Signup and view all the answers

What does S2 correspond to in the heart cycle?

Opening of the semilunar valves (D) Signup and view all the answers

What is the normal range for cardiac output in liters per minute?

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

Which factor contributes to an increase in cardiac output?

Increased heart rate (A) Signup and view all the answers

What is the formula to calculate cardiac output?

$CO = HR * SV$ (B) Signup and view all the answers

What is the ejection fraction formula in terms of end-diastolic volume (EDV) and end-systolic volume (ESV)?

$EF = SV / EDV$ (A) Signup and view all the answers

What is the main function of the endothelium in the heart?

Release vasoconstrictor hormones (A) Signup and view all the answers

What is the purpose of the fossa ovalis in the heart?

Was an opening while a fetus (C) Signup and view all the answers

Which chamber of the heart has a small contractile phase and contains pectinate muscles?

Right atrium (D) Signup and view all the answers

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

Help in cardiac conduction (C) Signup and view all the answers

Which valve in the heart has no muscular attachments but makes an audible sound as it closes?

Pulmonary valve (B) Signup and view all the answers

What is the main role of coronary veins in the heart?

Bring deoxygenated blood back to the right atrium (D) Signup and view all the answers

What is the function of desmosomes in cardiac muscle cells?

Prevent cells from ripping apart (A) Signup and view all the answers

Which structure in the heart serves as the pacemaker and sets the normal cardiac rhythm?

Sinoatrial node (A) Signup and view all the answers

What is responsible for creating spontaneous depolarization in cardiac conductive cells?

$\text{Na}^+$ channels open (B) Signup and view all the answers

Which characteristic is unique to cardiac contractile cells during repolarization?

They plateau before repolarizing (A) Signup and view all the answers