Cardiovascular System: The Heart

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What happens to the Ca++ channels at 0mV during repolarization?

They start a plateau phase

They become inactive

They open

They close (correct)

Which component of the ECG represents the depolarization of the ventricles?

U wave

P wave

T wave

QRS complex (correct)

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

To record electrical signals

To correct fibrillations

To induce a long refractory period

To deliver electrical impulses for effective contractions (correct)

What happens if the SA node were to fire 100 times per minute?

It would lead to a higher heart rate (C) Signup and view all the answers

How do slow Ca++ channels contribute to cardiac function?

By allowing for a plateau phase (C) Signup and view all the answers

What is the primary function of AEDs (Automated External Defibrillators) in cardiac emergencies?

To deliver corrective shocks for fibrillations (D) Signup and view all the answers

What is the function of the atria in the heart?

Collect blood and push it into lower chambers (D) Signup and view all the answers

Which structure is superior and medial to the apex of the heart?

Base (C) Signup and view all the answers

What is the primary function of the myocardium?

Contains muscle cells, nerve fibers, and blood vessels (D) Signup and view all the answers

Which vessel is the only artery to carry deoxygenated blood?

Pulmonary artery (D) Signup and view all the answers

Where are the great veins (superior and inferior vena cava) and arteries (aorta and pulmonary trunk) attached to the heart?

At the base (A) Signup and view all the answers

Which layer of the heart produces lubricating fluid?

Epicardium (A) Signup and view all the answers

What is the main function of endothelins released by the endothelium?

Regulate growth patterns of cardiac muscle cells (B) Signup and view all the answers

Which of the following statements about the septum is correct?

Physical extensions of the myocardium are present in it (B) Signup and view all the answers

What structures close the tricuspid valve to prevent backward flow into the right atrium?

Papillary muscles (D) Signup and view all the answers

Which chamber of the heart has a thicker muscle and no moderator band?

Left ventricle (C) Signup and view all the answers

What is the primary purpose of valves in the heart?

To ensure unidirectional blood flow (B) Signup and view all the answers

Which statement about semilunar valves is accurate?

They separate ventricles from blood vessels (B) Signup and view all the answers

What is the purpose of anastomosis in coronary circulation?

To provide collateral circulation in case of blockages (D) Signup and view all the answers

What defines myocardial conducting cells from myocardial contractile cells?

% involved in initiating and conducting action potentials (B) Signup and view all the answers

Where are T-tubules predominantly located in cardiac muscle cells?

At Z discs (D) Signup and view all the answers

What is the main role of desmosomes in cardiac muscle cells?

To prevent cardiac muscle cells from ripping apart during contractions (A) Signup and view all the answers

Which structure functions as the normal pacemaker of the heart?

Sinoatrial node (SA node) (A) Signup and view all the answers

What is the significance of plateau phase in cardiac contractile cells?

It maintains a sustained contraction to push blood effectively (C) Signup and view all the answers

Cardiovascular System: The Heart - Chapter 19.1 Quiz

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