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Coronary arteries are filled with blood during atrial contraction: Coronary arteries are primarily perfused during diastole, not atrial contraction. During systole, contraction of the ventricles compresses the coronary vessels, reducing blood flow.

Coronary circulation occurs only during systole: Coronary blood flow mostly occurs during diastole, because the myocardial contraction during systole compresses the coronary vessels, especially in the left ventricle.

Coronary arteries supply deoxygenated blood to the heart muscle: Coronary arteries supply oxygenated blood to the heart muscle, not deoxygenated blood.

Heart failure: Heart failure involves impaired cardiac output due to structural or functional heart abnormalities. Although pericardial effusion can eventually reduce cardiac output, the direct complication of excessive fluid is not standard heart failure but cardiac tamponade, a more acute and dangerous condition.

Pulmonary embolism: Pulmonary embolism occurs when a clot lodges in the pulmonary arteries. It is unrelated to pericardial fluid accumulation and arises from thromboembolic events, not fluid pressure on the heart.

Myocardial infarction: Myocardial infarction occurs due to coronary artery blockage, leading to ischemia. While tamponade can reduce cardiac output, it does not directly cause a myocardial infarction.

Aortic valve: The aortic valve is best heard at the second intercostal space, right sternal border, where blood exits the left ventricle into the aorta. Confusing these areas may lead to misidentifying murmurs.

Tricuspid valve: The tricuspid valve is auscultated along the lower left sternal border, 4th-5th intercostal space, and controls blood flow from the right atrium to the right ventricle. Murmurs here indicate right-sided valvular problems.

Mitral valve: The mitral valve is heard at the apex, 5th intercostal space at the midclavicular line. This valve regulates flow from the left atrium to the left ventricle. Misidentification can delay recognition of left-sided valvular pathology.

To produce pericardial fluid: The pericardium, not the myocardium, secretes pericardial fluid to reduce friction during cardiac movement. Confusing these structures may lead to misunderstanding cardiac physiology.

To protect the heart from external injury: Protection is primarily provided by the pericardium and thoracic cage. The myocardium’s main role is mechanical contraction, not external protection.

To facilitate the electrical conduction in the heart: Electrical conduction is carried out by specialized nodes and fibers (SA node, AV node, bundle of His, Purkinje fibers). The myocardium responds to these signals but does not generate the primary conduction itself.

Peripheral edema: Peripheral edema is a hallmark of right ventricular failure, resulting from systemic venous congestion. While left ventricular failure may eventually lead to right-sided symptoms if chronic, it is not the initial manifestation.

Jugular venous distention: Jugular venous distention indicates right-sided heart congestion due to elevated venous pressure, not left ventricular failure.

Hepatomegaly: Hepatomegaly occurs with right-sided heart failure, as venous congestion affects the liver. It is not a primary symptom of left ventricular dysfunction.

They are the primary mechanism of blood pressure regulation: Blood pressure is primarily regulated by the autonomic nervous system, baroreceptors, and vascular resistance. Skeletal muscle pumps assist venous return but are not the main regulatory mechanism for arterial pressure.

They control arterial blood pressure directly by contracting: Skeletal muscle pumps act on veins, not arteries. They cannot directly control arterial blood pressure because arteries have thicker muscular walls and are regulated by vascular tone, not skeletal muscle contraction.

They regulate arterial constriction during physical activity: Arterial constriction is controlled by smooth muscle in the arterial walls, influenced by the sympathetic nervous system, not by skeletal muscle activity.

Between the left ventricle and aorta; prevents backflow of blood into the left ventricle: This describes the aortic valve, not the mitral valve. The aortic valve prevents backflow from the aorta into the left ventricle. Confusing these can lead to misinterpretation of murmurs or heart sounds.

Between the right atrium and right ventricle; prevents backflow of blood into the right atrium: This describes the tricuspid valve, which is on the right side of the heart. The mitral valve is on the left side.

Between the right ventricle and pulmonary artery; prevents backflow of blood into the right ventricle: This describes the pulmonic valve, which is located at the right ventricular outflow tract, not the mitral valve.

The circumflex artery supplies the anterior wall of the left ventricle: The circumflex artery usually supplies the lateral and posterior walls of the left ventricle, not the anterior wall. The left anterior descending (LAD) artery supplies the anterior wall. Misidentification can affect understanding of myocardial infarction patterns.

The circumflex artery supplies the interventricular septum, crucial for left ventricular function: The interventricular septum is primarily supplied by the LAD artery, not the circumflex artery. The septum is crucial for coordinated left ventricular contraction.

The left anterior descending artery exclusively supplies the right ventricle: The LAD artery primarily supplies the anterior wall and interventricular septum of the left ventricle, not the right ventricle. Misunderstanding this can lead to errors in predicting areas affected during infarction.

Atrioventricular (AV) node: The AV node can act as a secondary pacemaker if the SA node fails, but its intrinsic rate (40-60 bpm) is slower than the SA node. Its primary role is delaying conduction to allow ventricular filling, not initiating the heartbeat.

Purkinje fibers: Purkinje fibers conduct impulses rapidly throughout the ventricles but do not serve as the primary pacemaker. They can act as a backup pacemaker at 20-40 bpm if higher centers fail.

Bundle of His: The Bundle of His transmits impulses from the AV node to the ventricles. While it is part of the conduction system, it cannot independently set the heart rate under normal conditions.

It supplies the interventricular septum: The interventricular septum is mainly supplied by the left anterior descending (LAD) artery. The RCA contributes only partially via its posterior descending branch in some individuals (right-dominant circulation).

It supplies the left ventricle: While the RCA can supply parts of the left ventricle inferiorly in some cases, the main supply to the left ventricle comes from the LAD and circumflex arteries.

It supplies the left atrium: The left atrium is mainly supplied by the circumflex artery, not the RCA. Misunderstanding this can affect predictions of infarct locations.