Question 1

The semilunar valves are positioned between the atria and ventricles.

Accepted Answer

The semilunar valves are positioned between the ventricles and the arteries (pulmonary artery and aorta). The atrioventricular valves are positioned between the atria and ventricles.

Question 2

The heart valves are innervated by the autonomic nervous system.

Accepted Answer

Heart valves do not have a direct innervation by the autonomic nervous system; they function mechanically to regulate blood flow and do not require nervous input to operate.

Question 3

The function of the chordae tendineae and papillary muscles is to hold the AV valves wide open during diastole to ensure complete ventricular filling.

Accepted Answer

The function of the chordae tendineae and papillary muscles is to prevent the AV valves from prolapsing (inverting) into the atria during ventricular contraction (systole). This allows for proper flow of blood from the atria to the ventricles and prevents backflow. During diastole, the AV valves close to prevent backflow of blood from the ventricles into the atria.

Question 4

The heart is posterior to the sternum.

Accepted Answer

The heart is located in the chest cavity and is located behind (posterior to) the sternum or breastbone.

Question 5

The right ventricle pumps out blood low in oxygen content, whereas the left ventricle pumps out blood high in oxygen content.

Accepted Answer

This statement is true. The right ventricle pumps deoxygenated blood to the lungs to be oxygenated, while the left ventricle pumps oxygenated blood to the rest of the body.

Question 6

The action potential spreads through the atria by gap junctions, but there are no gap junctions present in the ventricles, so the impulse must be propagated throughout the ventricular myocardium by the bundle of His and Purkinje system.

Accepted Answer

Both the atria and ventricles contain gap junctions that allow for the direct spread of electrical impulses between adjacent cells. The bundle of His and Purkinje system specifically facilitate rapid conduction throughout the ventricles, not because gap junctions are absent, but to ensure efficient and coordinated ventricular contraction.

Question 7

Arteries carry blood toward the ventricles.

Accepted Answer

Arteries carry blood away from the ventricles, not towards them.

Question 8

The aortic valve prevents backflow of blood from the aorta into the left ventricle during ventricular diastole.

Accepted Answer

This statement is true. The aortic valve is located between the left ventricle and the aorta, and it closes during ventricular diastole to prevent backflow of blood from the aorta back into the left ventricle.

Question 9

Cardiac tamponade refers to failure of the AV node to transmit the action potential from the atria to the ventricles.

Accepted Answer

Cardiac tamponade refers to the accumulation of fluid in the pericardial sac around the heart, which can compress the heart and impede its ability to pump effectively. It does not directly affect the conduction system of the heart, including the AV node.

Question 10

What is a metabolic predictor of heart disease that is independent of one's cholesterol/lipid profile

Accepted Answer

Homocysteine is a metabolic predictor of heart disease that is independent of one's cholesterol/lipid profile. High levels of homocysteine in the blood have been found to be associated with an increased risk of heart disease. HDL and VLDL are both types of cholesterol and are thus related to lipid profiles, while methionine is an amino acid and not directly related to heart disease risk.

Question 11

The functional syncytia of the myocardium are offered by the intercalated discs.

Accepted Answer

The intercalated discs of the myocardium are specialized cell-to-cell junctions that allow for functional and electrical coupling between cardiac muscle cells (cardiomyocytes), leading to their synchronization and contractile function as a functional syncytium. Therefore, the statement "The functional syncytia of the myocardium are offered by the intercalated discs" is true.

Question 12

The T wave represents the depolarization of the ventricles.

Accepted Answer

The T wave represents the repolarization of the ventricles.

Question 13

The action potential impulse passes through the AV node between the P wave and QRS complex.

Accepted Answer

The action potential impulse does pass through the AV node between the P wave and QRS complex. This is the delay point where the impulse becomes slowed down to allow for the ventricles to fill with blood before contracting.

Question 14

When does blood flow occur through the coronary circulation

Accepted Answer

Blood flow through the coronary circulation mainly occurs during diastole when the heart muscle is relaxed and the coronary arteries can fill with blood. During systole, the heart muscle contracts to pump blood out of the heart, which can briefly decrease blood flow through the coronary arteries. However, some blood flow can still occur during systole due to the elasticity of the arteries. Therefore, option B is the best choice as it accurately states that blood flow mainly occurs during diastole.

Question 15

The bundle of His and Purkinje system facilitate the rapid spread of the action potential throughout the ventricles.

Accepted Answer

The bundle of His and Purkinje system are specialized conducting fibers that allow for the rapid conduction of the electrical impulse throughout the ventricles, resulting in rapid myocardial contraction and ejection of blood from the heart.

Question 16

The only point of electrical contact between the atria and the ventricles is the AV valve.

Accepted Answer

The only point of electrical contact between the atria and the ventricles is through the atrioventricular (AV) node, not the AV valve. The AV node conducts the electrical impulse from the atria to the ventricles.

Question 17

The SA node is the pacemaker of the heart.

Accepted Answer

The SA node, or sinoatrial node, is a specialized group of cells located in the right atrium of the heart that generates electrical impulses, which spread throughout the heart and cause the heart to beat. Therefore, it is considered the natural pacemaker of the heart.

Question 18

The AV valve controls the amount of blood entering the atrium from the venous system.

Accepted Answer

The AV (atrioventricular) valve controls blood flow from the atria to the ventricles, not from the venous system into the atria.

Question 19

The tricuspid prevents regurgitation of blood from the right ventricle back into the right atrium.

Accepted Answer

The tricuspid valve is located between the right atrium and right ventricle and its main function is to prevent backflow of blood from the right ventricle to the right atrium during ventricular contraction.

Question 20

The pulmonary circulation carries oxygenated blood from the lungs to the body tissues.

Accepted Answer

The pulmonary circulation carries deoxygenated blood from the body tissues to the lungs to be oxygenated. The systemic circulation carries oxygenated blood from the heart to the body tissues.

Quiz 8: Cardiac Physiology