Understanding the basic structure and function of the heart will allow better insight into how
diseases of the heart can affect your pet’s health.
Below is a video of the normal human heart which is very similar to the dog or cat heart.
Blood returning from the body is collected in the right atrium before entering the right ventricle through the open tricuspid valve. The right ventricle then pumps the blood out through the then open pulmonic valve through the pulmonary artery to the lungs. Meanwhile the tricuspid valve closes preventing retrograde (backflow) flow of blood. After the carbon dioxide is removed and the blood is re-oxygenated it is transported via the pulmonary veins to the collecting chamber called the left atrium.
Then, similar to the right heart, the blood is transported through the mitral valve into the powerful left ventricle. When the left ventricle is full and begins to contract, the mitral valve closes, and blood is ejected through the now open aortic valve to the aorta and to the systemic circulation. After delivering oxygen to the tissues and accumulating carbon dioxide, the blood completes the cycle back to the right atrium again.
Right Atrium → Tricuspid Valve →Right Ventricle → Pulmonic Valve →Pulmonary Artery →Lungs (oxygenation) →Pulmonary Veins →Left Atrium → Mitral Valve →Left Ventricle → Aortic Valve →Aorta →Tissues (oxygen delivery) →Systemic Veins → Right Atrium