Types Of Circulatory System

Fluid circulation of body is of several types.

Intracellular Circulation

It occurs in unicellular organisms as well as individual cells of multicellular organisms. The cytoplasm shows regular streaming movement, called cyclosis. Ex - Protozoa.

Extracellular circulation

Extraorganismic circulation:

Lower animals lack proper circulatory system, use water as the circulatory fluid.

Sponges have canal system. Water enters body with food and O2 through ostia, passing through canals goes out through osculum with the waste products.

In coelenterates (Hydra) fluid flows in a single cavity, coelenteron (gastro-vascular cavity) entering through mouth and passing back through same.

Echinoderms have water vascular system (ambulacral system) as its special characteristics.

Intraorganismic Circulation

The body has its own circulating fluid.

Parenchymal Circulation: The space between internal organs and body wall contains a special tissue of irregular cells known as parenchyma. It encloses a network of fluid filled spaces. Body movements cause circulation of parenchymal fluid. e.g. Platyhelminthes.

Coelomic Circulation: In Aschelminthes, pseudocoelomic fluid takes part in transport of materials. In Arthropoda haemocoel is present that contain blood (Haemolymph) instead of coelomic fluid.