Mesodermal tissue is one of the three primary germ layers formed during embryonic development, alongside the ectoderm and endoderm. It plays a crucial role in the formation of various structures in the body, including muscles, bones, and the circulatory system. This layer is responsible for developing many internal organs and connective tissues. In vertebrates, mesodermal tissue arises during the process of gastrulation, where cells migrate and differentiate. It can be further divided into several regions, such as paraxial mesoderm, which forms somites, and lateral plate mesoderm, which contributes to the formation of the heart and blood vessels.