Which one of the following valves guards the opening between the right ventricle and the pulmonary artery?
- A.Bicuspid valve
- B.Semilunar valve
- C.Mitral valve
- D.Tricuspid valve
Correct answer
Explanation
The correct answer is B, Semilunar valve. The opening of the pulmonary artery from the right ventricle is guarded by the pulmonary semilunar valve, which stops blood from flowing back into the ventricle when it relaxes. The human heart has four chambers and four main valves. Two atrioventricular valves lie between the upper and lower chambers: the tricuspid valve on the right side and the bicuspid valve on the left side. Two semilunar valves, named for their half-moon shaped flaps, guard the exits of the ventricles: the pulmonary valve at the pulmonary artery and the aortic valve at the aorta. The closing of these valves produces the heart sounds lub and dub. Option A is wrong because the bicuspid valve lies between the left atrium and the left ventricle. Option C is wrong because the mitral valve is simply another name for the bicuspid valve. Option D is wrong because the tricuspid valve lies between the right atrium and the right ventricle, not at the pulmonary artery. Exam tip: tricuspid = right atrium to right ventricle; bicuspid (mitral) = left side; semilunar = exits to aorta and pulmonary artery.
Practice Questions
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