0These circulation systems are also called transport systems and mass transport systems, the term 'mass transport' referring to the fact that something, i.e. the circulatory fluid and all the solutes dissolved within it, is being moved in volume. This can be compared with lots of people travelling by train as opposed to making their own way via different routes and modes of transport.
The 2 types of circulation systems in animals are:
- Open Circulatory Systems (Open Circulation Systems)
e.g. in insects, where there may be some vessels but the circulatory fluid - 'hemolymph', also written 'haemolymph' - flows out of the vessels that form the circulatory system and bathes tissues directly. That is, instead of the blood capillaries in closed circulatory systems (see below), the main vessels in open circulatory systems open into open sinuses. - Closed Circulatory Systems (Closed Circulation Systems)
e.g. in vertebrates such as fish and mammals, blood is contained within the structure of the heart and blood vessels that have a range of sizes and structures, including arteries, arterioles, capillaries, venules and veins. Larger blood vessels move blood around the body, taking it from organ to organ, through the blood system, which is also called the vascular system. Substances pass between the blood and the tissues it supplies by moving through the thin walls of the smallest blood vessels, which are called capillaries.
