Closed circulatory system= blood is enclosed in blood vessels and does not come directly into contact with the cells of the body.
Open circulatory systems= there are very few vessels to contain the transport medium so it is pumped straight from the heart into the body cavity of the animal (haemocoel).
Single closed circulatory system= blood flows through the heart and is pumped out to travel all around the body before returning to the heart. (blood travels only once through the heart for each complete circulation).
Double closed circulatory system= involves two separate circulations. Blood is pumped from the heart to the lungs to pick up oxygen and unload carbon dioxide and then returns to the heart. Blood then flows through the heart and is pumped out to travel all around the body before returning to the heart again.
Double circulatory system= blood travels twice through the heart for each circuit of the body. Each circuit only passes through one capillary network, which means a relatively high pressure and fast flow of blood can be maintained.