What is the Difference Between Coelom and Haemocoel?

The main difference between a coelom and a haemocoel lies in their origin, function, and the animals that possess them:

• Coelom:
• Originates from mesothelium and serves as the principal body cavity of annelids, echinoderms, and chordates.
• Lined by mesodermal epithelium and is filled with coelomic fluid.
• Examples include annelids to chordates.
• Haemocoel:
• Primarily found in arthropods and mollusks, serving as a reduced form of a coelom.
• Lined by the basal lamina of the epithelial sheet and filled with circulatory fluids, including blood.
• Blood circulates through the haemocoel, playing a role in the circulatory system.
• Examples include mollusks and arthropods.

In summary, a coelom is a fluid-filled main body cavity found in annelids, echinoderms, and chordates, while a haemocoel is a primary body cavity filled with circulatory fluids, typically found in arthropods and mollusks.

Comparative Table: Coelom vs Haemocoel

The main differences between coelom and haemocoel are as follows:

In summary, the coelom is a true perivisceral cavity that develops within the mesoderm during the embryonic stage and is lined by coelomic epithelium. It is the principal body cavity of echinoderms, chordates, and annelids. On the other hand, the haemocoel is a primary body cavity filled with circulatory fluids and is lined by the basal lamina of the endothelium. It is found in arthropods and molluscs.