Fish heart, chambers (Gross, Low)

Structure List Heart Liver Spleen Testis Intestinal ceca Transverse septum

In fish, the pericardial cavity is surrounded by firm tissues on the parietal surfaces. Shown here is the transverse septum, which separates the pericardium from the liver. Volume changes within the pericardium help suck blood into the sinus venosus from the large veins.