The tricuspid valve is located between the

Analyze the question: You're asked where the tricuspid valve sits in the mammalian heart.

Concept: Heart valves keep blood flowing in one direction. Each valve sits between two specific chambers or vessels:

| Valve | Location | |---|---| | Tricuspid (right atrioventricular) | Between the right atrium (auricle) and right ventricle | | Bicuspid / Mitral (left atrioventricular) | Between the left atrium (auricle) and left ventricle | | Aortic semilunar | Between the left ventricle and the aorta | | Pulmonary semilunar | Between the right ventricle and the pulmonary artery |

Step-by-step solution:

1. "Tricuspid" means "three flaps" (tri = three, cusp = flap). This valve is on the right side of the heart.
2. It is an atrioventricular valve, so it lies between an auricle (atrium) and a ventricle on the same side.
3. On the right side, that means between the right auricle and right ventricle.
4. Checking the options: • A. Right auricle and right ventricle: correct. • B. Aorta and left ventricle: this is the aortic semilunar valve. • C. Left auricle and left ventricle: this is the bicuspid (mitral) valve. • D. Right auricle and superior vena cava: no major valve is located here.

Answer: A

Function: When the right auricle contracts, blood passes through the tricuspid valve into the right ventricle. When the ventricle contracts, the valve closes to prevent backflow, and blood goes to the lungs through the pulmonary artery.

Exam tip: Remember "Tri on the Right": both have an "R" sound, and the tricuspid valve is on the right. The bicuspid (two flaps) is on the left, and "LAB" helps too: Left Atrium Bicuspid.