Question

The inlets of the left atrium is guarded by

• A. Thebesian valve
• B. Eustachian valve
• C. Mitral valve
• D. None of the above

Answer 1

The correct option is D None of the above

The inlets of the left atrium are the pulmonary veins which carry oxygenated blood from the lungs to the heart. There are four pulmonary veins in case of humans. The four openings of these veins are not guarded by any valves.

The thebesian valve guards the opening of the coronary sinus into the right atrium. It prevents any backflow of deoxygenated blood from the right atrium to coronary sinus.
The eustachian valve is present at the opening of the inferior vena cava into the right atrium.
Mitral valve is the other name of the bicuspid valve which is present between the left atrium and left ventricle.