Types Of Circulatory System
Circulatory System of Class 11
Fluid circulation of body is of several types.
It occurs in unicellular organisms as well as individual cells of multicellular organisms. The cytoplasm shows regular streaming movement, called cyclosis. Ex - Protozoa.
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.
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.