Evolution of the Vertebrate Heart Two Chambers: Two Chambers plus Septa: Three Chambers: Four Chambers: Human Heart Anterior and Posterior Vena Cava Right Atria Atrioventricular (AV) Valve (tricuspid) Right Ventricle Semilunar Valve Pulmonary Arteries Lungs Pulmonary Veins Left Atria Atrioventricular (AV) Valve (bicuspid) Left Ventricle Semilunar Valve Aorta Body Circulatory Schemes
Evolution of the Vertebrate Heart Two Chambers: Two Chambers plus Septa: Three Chambers: Four Chambers: Human Heart Anterior and Posterior Vena Cava Right Atria Atrioventricular (AV) Valve (tricuspid) Right Ventricle Semilunar Valve Pulmonary Arteries Lungs Pulmonary Veins Left Atria Atrioventricular (AV) Valve (bicuspid) Left Ventricle Semilunar Valve Aorta Body Circulatory Schemes