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

Step 1: Set up the heart chambers.
The human heart has four chambers, two atria above and two ventricles below, and valves keep blood flowing in one direction.
Step 2: Focus on the right side.
Deoxygenated blood enters the right atrium and must move down into the right ventricle through the right atrioventricular opening.
Step 3: Name that valve.
The right atrioventricular opening is guarded by the tricuspid valve, which has three cusps.
Step 4: Rule out the SA node.
The sino-atrial node is the pacemaker that generates impulses in the right atrial wall, but it is not a valve, so it is wrong.
Step 5: Rule out bicuspid and semilunar valves.
The bicuspid (mitral) valve guards the LEFT atrioventricular opening, and semilunar valves sit where the arteries leave the ventricles. Neither guards the right atrioventricular opening.
Step 6: Conclude.
The opening between the right atrium and right ventricle is guarded by the tricuspid valve.
\[ \boxed{\text{tricuspid valve}} \]