The conus arteriosus is one of two accessory chambers found in most fish with two-chambered hearts, explains an East Carolina University biology website. The primary function of the conus arteriosus is to prevent the backflow of blood and keep a steady flow of blood into the ventral aorta and the gills.
The conus arteriosus has a funnel-shaped structure and is located in the right ventricle of the heart. The pulmonary artery originates from this conical extension of the right ventricle. The conus arteriosus regulates the flow of blood into the aorta and gills by contracting. This cardiovascular structure also acts to increase blood pressure by preventing the backflow of blood.
The conus arteriosus is involved in the movement of blood from the right ventricle into the pulmonary artery. The location of this accessory chamber allows it to help keep oxygen-rich blood separate from oxygen-poor blood.
The conus arteriosus also plays a part in maintaining an osmotic balance in the ventricle. The wall of the conus arteriosus consists of a thin layer of cardiac muscle overlapping an elastic coat. This structure consists of various sets of upper, middle and lower valves. Multiple small valve cusps are interposed between the middle and lower valves.