Physiology of the Amphibian Heart

Physiology of the Amphibian Heart

April 13, 2007

Introduction
The heart is one of the most important organs in the body. It is responsible for pumping blood throughout the body. This blood carries oxygen, nutrients, and signaling molecules (like hormones) to cells, and carries waste products away from cells. The heart is a pair of valved muscular pumps combined in a single organ.1 In mammals, there are four cardiac chambers, the two atria receive venous blood as weakly contractile reservoirs for final filling of the two ventricles which then provide the powerful expulsive contraction force that forces blood into the main arterial trunks.1 In the frog, however, there are only three chambers: two atria and one ventricle.6 The atria are in the upper part of the heart and the ventricles are in the lower part of the heart. They are separated from each other by a mixture of fibrous and fatty tissue, and two valves on each side which prevent blood from entering either chamber at the incorrect time.2 In mammals, the valve on the right side is called the Tricuspid valve, while that on the left side is called the Mitral valve.1