Science / Biology / Mesoderm: The middle layer of cells in embryonic development; gives rise to muscles, bones, and structures associated with reproduction. The middle embryonic tissue layer. Cells and structures arising from the mesoderm include the bone, blood, muscle, skin, and reproductive organs.

Connective Tissue

Science / Biology / Connective Tissue: Animal tissue composed of cells embedded in a matrix (gel, elastic fibers, liquid, or inorganic minerals). Includes loose, dense, and fibrous connective tissues that provide strength (bone, cartilage) MORE


Science / Biology / Somites: Mesodermal structures formed during embryonic development that give rise to segmented body parts such as the muscles of the body wall. MORE


Science / Biology / Notochord: In chordates, a cellular rod that runs the length of the body and provides dorsal support. Also, a structure of mesoderm in the embryo that will become the vertebrae of the spinal column. The stiff ro MORE


Science / Biology / Coelomates: Animals that have a coelom or body cavity lined with mesoderm. MORE


Science / Biology / Pseudocoelomates: Animals that have a body cavity that is in direct contact with the outer muscular layer of the body and does not arise by splitting of the mesoderm; e.g., roundworms. MORE