Question

A spiral valve is present
A) Sinus venosus of frog’s heart
B) Right auricle of rabbit’s heart
C) Pylangium of the conus arteriosus of frog’s heart
D) Synangium of the conus arteriosus of frog’s heart

Answer 1

Valves are flap-like structures present in the heart that prevents the backflow of blood, thus promoting the flow of blood in only one direction.

Complete answer:
The heart is the organ of the body that is involved in pumping blood to different locations. The structure of the heart is different in different organisms. For example fishes have two chambered hearts, amphibians and reptiles have three chambered hearts and humans and birds have four chambered hearts. The heart of frogs contains two additional chambers- conus arteriosus that distribute blood to the body and sinus venosus that receives blood from the body. The conus arteriosus of the heart is the region that consists of the spiral valve. The spiral valve plays a very important role in directing the blood flow. At first the venous blood enters to the right atrium through sinus venosus. It then moves to the left atrium and following contraction moves to the ventricle. The blood in the right atrium goes to lungs and skin for oxygenation and the blood in the left atrium goes to the head. Thus the blood in two of the atrial chambers are different, this difference in composition in them is also maintained in the ventricle by the spiral valve.
So the correct option is (C) Pylangium of the conus arteriosus of frog’s heart.

Note: The spiral valve is of importance as it not only keeps the blood with different composition separately but also passes the blood to the arterial arch from where it is transported throughout the body.