Cardiovascular SYstem
Lettuce Coral have another different form of cardiovascular system that is present in the animal kingdom. Their cardiovascular system is not individual, but rather combined with the digestive system. This is known as a gastrovascular system. This system works in the form of a gastrovascular cavity, which is the main area for digesting substances and distributing them as well. The gastrovascular cavity is located at the center of a polyp, and is opened up toward water. The nutrients and oxygen gained through the coral's outer cell layers can then in turn diffuse through its body. Small algae called zooxanthellae are able to live symbiotically off coral through this distribution system in turn.