Name and outline the two types of circulatory systems

A single circulatory system is where blood flow starts with deoxygenated blood being pumped by the heart to the lungs or gills and then travelling directly to the rest of the body’s tissues. Found in fish and amphibians. a double circulatory system is where deoxygenated blood is pumped to the lungs where it becomes oxygenated and then travels back through a second chamber in the heart which pumps oxygenated blood to the rest of the body to its respiring tissues. Found in larger animals like mammals who require a higher blood pressure for sufficient oxygen supply.