Mesenchyma

Mesenchyme - embryonic germ that serves as a source of development of connective tissue, blood, skeletal and smooth muscle. Mesenchyma consists of loosely lying cells with branches and intercellular liquid, located in the primary body cavity between embryonic leaves.
Cm. also the Germ.

Mesenchyme (from the Greek. mesos - average and enchyma - content filling mass) is one of the rudimentary representing loosened part of the middle embryonic leaf, or the mesoderm.
In vertebrates, mesenchyma arises from Samitov in places loosening their plots of dermatomes and sclerotome, as well as through eviction of cells from the visceral and parietal leaves splanchnotomy. Originating from dermatomes mesenchyma differentiated in the connective tissue framework of the skin (the skin, or the dermis). Sclerotomy give rise sclerogenous the mesenchyme, differentiate into cartilage and bone. Vasilyuhina from splanchnotomy cell mesenchyme form the connective tissue, blood and lymphatic vessels, blood cells and lymph, smooth muscle tissue of viscera. Thus, M is generally in vertebrates an embryo of a wide group of fabrics internal environment. Growing from her smooth muscle tissue in many properties closer to the connective tissue than to skeletal muscle. In vertebrates and the man some M not formed from the mesoderm, and of neuroectodermal of the embryo, namely neural crest, or the ganglion plate ectomesenchyme, or nanomaterial). From it there chromatophores from (pigment cells), some of the cartilages of the larynx may pulp of teeth and cells - the originators of dentin (odontoblast).
Mesenchyme in the period of its origination process consists of cells, sitewide United processes. The gaps between the cells filled intercellular fluid. Individual cells can develop processes, to escape from communication with other cells and, ameboid moving through logmanager, phagocytose bacteria and other foreign particles, trapped in the body of the embryo. Thus, M. consists of a fixed (settled) and mobile cells that can turn into each other. Together with the intercellular fluid and they constitute the internal environment of the embryo. In the first stages of development mesenchyma still lacks a special tissue structures (fibers, etc.,) and is embryonic germ, not cloth. However, its separate parts (especially those that are part of the subsidiary bodies of the embryo) very early tissue undergoing specialization, turning into embryonic connective tissue, blood cells, and so on, According to most histologists, vascular endothelial also develops from M. However, some consider "th originating from special vascular embryo - angioblast, the cells of which is involved in M, outwardly indistinguishable from its cells. Already in embryo, the whole mesenchyma spent on education tissues. Cambial (undifferentiated) cells of the connective tissue of children's and adult organism qualitatively different from M germ relatively higher level of differentiation. Therefore, the concept of "mesenchyme adult" or "mesenchymal reserve" groundless: the part of a differentiated body unchanged cells of the embryo are not saved. Cm. also the Mesoderm.