Describe the structure of the heart of frog.

The heart of frog is a muscular organ.
* It is 3-chambered with two atria and one ventricle.
* It is covered with pericardium.
* Sinus venosus is present on the dorsal side. It opens into right atrium.
* Ventricle opens into the conus arteriosus.
* Conus arteriosus divides into two.
* Each is further divided into three aortic arches called carotid, systemic, and pulmocutaneous.
* The circulation is incomplete (oxygenated and deoxygenated blood mix in the ventricle) and double (blood passes through the heart twice).