Question

Sinus venosus in mammals is believed to have merged with the wall of

• A. Right auricle
• B. Left auricle
• C. Right ventricle
• D. Left ventricle

Answer 1

The correct option is A Right auricle

The sinus venosus is a large quadrangular cavity, which precedes the atrium on the venous side of the chordate heart. In mammals, it exists distinctly only in the embryonic heart (where it is found between the two venae cavae). It also persists in the adult. In the adult, it is incorporated into the wall of the right atrium to form a smooth part, called as the sinus venarum, which is separated from the rest of the atrium by a ridge of fibers, called as the crista terminalis.

So, the correct answer is option A.