cardiovascular system of the apple snail
The apple snail has a well developed heart that consists of two chambers, and auricle and a ventricle. The auricle receives blood from the kidney and lung veins. When the auricle contracts, blood is sent into the much larger ventricle. When the blood enters the ventricle, it too contracts, forcing the blood to the rest of the snail's body. Though it is not part of the heart, there is another structure that plays an important role in regulating a snail's blood pressure. The aortic ampulla is a sac that compensates for the rise in blood pressure that results from a contraction of the ventricle.