Mesoglea

Mesoglea is a special material found in sea creatures like coral and jellyfish. It is part of the extracellular matrix, which means it is made outside of cells. This material helps these animals keep their shape.

Mesoglea is found in animals called cnidarians, which include jellyfish and coral, as well as in ctenophores, often called comb jellies. It helps these creatures stay firm and stable in the water.

This material is different from something called mesohyl, found in sponges. While both are made outside cells, they serve different purposes in their animals.

Description

The mesoglea is mostly made of water. It also contains special proteins like collagen and heparan sulfate proteoglycans. In animals like Cnidaria and Ctenophora, the mesoglea has tiny muscle and nerve bundles. It also has wandering cells called amoebocytes that help clean up debris and fight off harmful germs.

The mesoglea acts like an internal skeleton, giving support to the body. It can stretch and then return to its shape thanks to its stretchy properties. Without the support of water, it isn’t strong enough to hold up the body on its own, so these animals usually flatten or collapse when out of water. The mesoglea sits between two layers: the outer epidermis and the inner gastrodermis. In some bigger jellyfish, the outer layer may wear away, leaving the mesoglea directly exposed to the water.

Uses of the term

Some scientists use the word mesoglea to describe layers in animals like jellyfish and sponges. They do this to keep it separate from a similar word used in animal development studies.

Other scientists, like Brusca & Brusca in 2003, say mesoglea should only be used for certain animals and to keep the original word for development studies.