∞ generated and posted on 2016.08.31 ∞
Embryonic tissue that forms between the animal embryo's inner and outer layers.
Only triploblastic animals possess mesodermal tissue, which is in addition the ectodermal and endodermal tissue. The mesoderm thus represents the cellular "middle" between these two other layers, which in cnidarians instead is acellular.
Note that Body cavities, called coelom, are found within mesodermal tissue.
Among a number of mature tissues found in animals, both connective tissue (bone, cartilage, blood) and muscles are derived from mesodermal tissue.