Question

question 2

when the semilunar valves are open during the cardiac cycle, which of the following occur (choose all correct):

a. the tricuspid and bicuspid valves are closed
b. the ventricles are in systole (contracted)
c. the ventricles are in diastole (relaxed)
d. blood enters the aorta
e. blood enters the pulmonary trunk
f. the atria contract

Explanation:

Analyze semilunar valve opening

The semilunar valves (aortic and pulmonary) open when pressure inside the ventricles exceeds pressure in the great arteries. This occurs during ventricular ejection, which is a phase of ventricular systole.

Evaluate ventricular state

During ventricular systole, the ventricles are contracted to pump blood out. Therefore, the ventricles are in systole, not diastole.

Evaluate atrioventricular valves

To prevent backflow of blood into the atria during ventricular contraction, the atrioventricular valves (tricuspid and bicuspid/mitral) must be closed.

Determine blood flow direction

When the left ventricle contracts, blood is ejected through the open aortic semilunar valve into the aorta. When the right ventricle contracts, blood is ejected through the open pulmonary semilunar valve into the pulmonary trunk.

Evaluate atrial state

During ventricular systole, the atria are relaxed (in diastole) and filling with blood, not contracting.

Answer:

• A. the tricuspid and bicuspid valves are closed (Correct answer)
• B. the ventricles are in systole (contracted) (Correct answer)
• C. the ventricles are in diastole (relaxed)
• D. blood enters the aorta (Correct answer)
• E. blood enters the pulmonary trunk (Correct answer)
• F. the atria contract