Question

The opening between the right atrium and the right ventricle is guarded by

• A. sino-atrial node
• B. bicuspid valve
• C. tricuspid valve
• D. semilunar valve

Hint:

• Mnemonic to remember valve locations: itemize

• R-T: Right side has the Tricuspid valve.

• L-B: Left side has the Bicuspid (Mitral) valve.
The AV valves are attached to muscular projections called papillary muscles in the ventricular walls via fibrous cords called chordae tendineae, which prevent the valves from collapsing backward into the atria during ventricular contraction. itemize

Answer 1

The Correct Option is C

Concept:

• The human heart is divided into four chambers: two upper atria and two lower ventricles.

• To maintain unidirectional blood flow and prevent backflow, the openings between these chambers are regulated by specialized muscular valves: itemize

• Atrioventricular (AV) Valves: Positioned between the atria and the ventricles.

• Semilunar Valves: Positioned at the junctions where major arteries exit the ventricles.
itemize

Step 1: Analyze the right side of the heart
Deoxygenated blood from the systemic circulation enters the right atrium and must pass into the right ventricle. The right atrioventricular aperture connects these two chambers. This specific opening is guarded by the

tricuspid valve, which is composed of three distinct fibrous cusps or flaps.

Step 2: Evaluate the alternative options

• (A) Sino-atrial node (SAN): This is a specialized patch of neuromuscular tissue located in the upper wall of the right atrium. It serves as the natural pacemaker of the heart by generating electrical impulses, but it is not a physical valve.

• (B) Bicuspid valve: Also referred to as the mitral valve, this structure consists of two cusps and guards the opening between the left atrium and the left ventricle.

• (D) Semilunar valves: These half-moon-shaped valves guard the openings where the pulmonary artery leaves the right ventricle and where the aorta leaves the left ventricle.

Step 3: Formulate the final conclusion
Based on internal cardiac anatomy, the tricuspid valve regulates the passage of blood between the right atrium and right ventricle. Therefore, the correct option is (C).