3. A Frog's Heart Is Central to Its Circulation
It has two atria and a single ventricle, making it havea total of three chambers.
Here's howit works.
Deoxygenated blood is sentto the atrium from various organs in the frog's body
through blood vessels and veins. This is the blood being drained from organs, thus
starting the cleansing process. Oxygenated blood then comes from the lungs and
the skin, and enters the left atrium. (This also serves as a gas exchangein most
amphibians.)
Both atria dump their blood into the single ventricle. Theventricle is divided into
two narrowly separated chambers, which cleverlyreduces the mixing of
oxygenated and deoxygenated blood together. The ventricle contracts, sending
oxygenated blood tothe brain from the left ventricle. It reaches the head by flowing
through the carotid arteries.
This is an almost pure blood that reaches the brain.