Coelom: The body cavity, which is lined by mesoderm is called coelom. Animals possessing coelom are called coelomates, e.g., annelids, molluscs, arthropods, echinoderms, hemichordates and chordates . In some animals, the body cavity is not lined by mesoderm, instead, the mesoderm is present as scattered pouches in between the ectoderm and endoderm. Such a body cavity is called pseudocoelom and the animals possessing them are called pseudocoelomates, e.g., aschelminthes . The animals in which the body cavity is absent are called acoelomates, e.g., platyhelminthes.

Coelom Function

• Coelom works as a shock absorber and protects from any kind of mechanical shock. It gives more flexibility to the body organs to move and protects from any damage on minor bends by cushioning the internal organs
• The coelomic fluid acts as a hydrostatic skeleton, which helps in the locomotion of soft-bodied animals and gives the body a definite shape. Contracting muscles can push against the coelomic fluid because of the fluid pressure.
• The coelomocyte cells, that either float freely in the coelom or attached to the wall, support the immune system. They support the immune system by initiating humoral immune response and phagocytosis
• The coelomic fluid also helps in gaseous transport and transport of nutrients and waste products
• Coelom gives the extra space required by organs to develop and function. E.g. pumping action of the heart, carrying a child in the womb, etc. is possible due to coelom.

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By Team Learning Mantras