The human circulatory system
The heart pumps blood through the blood vessels. Together, the heart, blood and blood vessels make up the circulatory system which transports substances to, and away from, different parts of our body!
Our circulatory system is essential in keeping all parts of our body alive by carrying oxygen to different cells. When our flow of blood is interrupted, cells do not receive the oxygen they need to survive and start to die within minutes!
Fish and human circulatory systems
The circulatory system of fish is a single circulation – blood passes through the heart once in each circulation. However, humans have a double circulation, in which blood passes through the heart twice in each circulation.
Plant transport system
The water carrying tubes , or the xylem, and the food-carrying tubes, or the phloem, make up the transport system in plants.