Fish, arteries (Gross, Low)

Structure List Dorsal aorta Carotid artery Celiacomesenteric artery Dorsal segmental arteries An efferent branchial artery Gill vessels

Fish have SINGLE SYSTEMS of circulation where the heart has but one atrium and a single ventricle and the blood passes from the heart to the ventral aorta, then to the gills for oxygenation, and from there to the dorsal aorta for circulation to the body. Since blood pressure is reduced by passage through the gills, the system operates at low pressure levels relative to that of the double system where blood coming back to the heart from the lungs is given another boost in pressure as the left ventricle ejects it into the aorta.