Cardiac Electrical Conduction System

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Where is the base of the heart located?

Inferior and medial to the apex

Superior and medial to the apex (correct)

Superior and lateral to the apex

Inferior and lateral to the apex

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

Right ventricle

Left atrium (correct)

Right atrium

Left ventricle

Where does CO2 leave and O2 enter in the heart?

Aortic valve

Pulmonary capillaries (correct)

Superior vena cava

Atrial septum

Which artery is the only one to carry deoxygenated blood?

Pulmonary artery Signup and view all the answers

What is the function of auricles in the heart?

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

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

Myocardium Signup and view all the answers

During the cardiac cycle, which phase is characterized by the pumping of blood into circulation?

Systole Signup and view all the answers

What is the function of an artificial pacemaker in the heart?

Correcting fibrillations Signup and view all the answers

Which component of the ECG represents the repolarization of ventricles?

T wave Signup and view all the answers

What is the primary function of an AED (Automated External Defibrillator) in cardiac emergencies?

Correcting fibrillations Signup and view all the answers

Which phase of the cardiac cycle marks the relaxation of the ventricles and closing of semilunar valves?

Ventricular diastole Signup and view all the answers

What term is used to describe the amount of blood pushed out by the ventricles during each contraction?

Stroke volume Signup and view all the answers

What happens at 0mV in the heart?

Ca++ channels close and K+ channels open for typical repolarization Signup and view all the answers

What is the main purpose of the long refractory period in the heart?

To prevent premature contractions Signup and view all the answers

Which node would fire 80-100 times per minute if not for endocrine control?

SA node Signup and view all the answers

What is the abbreviation for 'Electrocardiogram'?

ECG Signup and view all the answers

What do electrodes placed on the body during an ECG record?

Electrical signals of the heart Signup and view all the answers

Which layer of the heart is responsible for releasing endothelins, strong vasoconstrictors?

Endocardium Signup and view all the answers

What is the function of the atrioventricular valves?

Opening during ventricular contraction Signup and view all the answers

What structure divides the heart into chambers and is a physical extension of the myocardium?

Septum Signup and view all the answers

Which event causes the 'lub' sound in a heartbeat?

Closing of atrioventricular valves Signup and view all the answers

Which valve separates the left atrium from the left ventricle?

Mitral valve Signup and view all the answers

What does an ejection fraction measure?

Percentage of blood pumped out of the ventricles Signup and view all the answers

What term describes the blood vessel interconnections that allow blood to flow even if there is a partial blockage?

Anastomosis Signup and view all the answers

How does exercise affect stroke volume?

Increases it Signup and view all the answers

Which cells in the heart conduct impulses and contract to pump blood through the body?

Myocardial conducting cells Signup and view all the answers

What is the function of the vagus nerve in heart rate regulation?

Slows heart rate Signup and view all the answers

What structure in the heart sets the normal cardiac rhythm and is known as the pacemaker?

Sinoatrial (SA) node Signup and view all the answers

Which factor can decrease heart rate?

Hypoxia (lack of O2) Signup and view all the answers

What is the total time from initial impulse to ventricle depolarization in the heart?

~225 ms Signup and view all the answers

What happens when there is less filling time in the heart?

Decreased end-diastolic volume Signup and view all the answers

Which ions are responsible for creating the spontaneous depolarization in cardiac conductive cells?

$Na^+$ and $Ca^{2+}$ Signup and view all the answers

When do the 4 chambers of the heart complete their development?

End of week 5 Signup and view all the answers

What happens during the plateau phase of cardiac contractile cells?

$Ca^{2+}$ channels close Signup and view all the answers

What causes a heart murmur?

Turbulent blood flow Signup and view all the answers

What do gap junctions in cardiac muscle cells allow for?

$ion$ movement Signup and view all the answers

What is the function of S2 in a heartbeat?

Opening of semilunar valves Signup and view all the answers