miðhúð

Miðhúð refers to the mesoderm, one of the three primary germ layers that form during early embryonic development in metazoan animals. It is located between the ectoderm, the outermost layer, and the endoderm, the innermost layer. The formation of the mesoderm is a critical step in gastrulation, the process by which the three germ layers are established.

The cells of the mesoderm differentiate into a wide variety of tissues and organs. These include the dermis of the skin, the muscles, the skeleton, the circulatory system (including the heart and blood vessels), the excretory system (such as the kidneys), and the reproductive organs. In vertebrates, the mesoderm is also responsible for forming the notochord, a flexible rod that provides skeletal support, and the somites, which give rise to the vertebrae, ribs, and skeletal muscles of the trunk and limbs. The mesoderm is divided into several subdivisions, each giving rise to specific structures. These typically include paraxial mesoderm, intermediate mesoderm, and lateral plate mesoderm, along with the notochord. The precise fate and organization of mesodermal cells vary somewhat among different animal groups, reflecting the diversity of body plans in the animal kingdom.