This allows them to form their large siliceous spicules exclusively inside their cells. Much of the body of Hexactinellid sponges is composed of syncitial tissue. The syncytial epithelium of the placenta does not provide such an access path from the maternal circulation into the embryo. This is probably important to limit the exchange of migratory cells between the developing embryo and the body of the mother, as some blood cells are specialized to be able to insert themselves between adjacent epithelial cells. Embryo-derived cells that form the interface with the maternal blood stream fuse together to form a multinucleated barrier – the syncytiotrophoblast. Osteoclasts Ĭertain animal immune-derived cells may form aggregate cells, such as the osteoclast cells responsible for bone resorption.Īnother important vertebrate syncytium is in the placenta of placental mammals. Smooth muscle in the gastrointestinal tract is activated by a composite of three types of cells – smooth muscle cells (SMCs), interstitial cells of Cajal (ICCs), and platelet-derived growth factor receptor alpha (PDGFRα) that are electrically coupled and work together as an SIP functional syncytium. Cardiac tissue is therefore described as a functional syncytium, as opposed to the true syncytium of skeletal muscle. Although a syncytium, cardiac muscle differs because the cells are not long and multinucleated. Cardiac action potentials propagate along the surface of the muscle fiber from the point of synaptic contact through intercalated discs. The syncytium of cardiac muscle is important because it allows rapid coordinated contraction of muscles along their entire length. Thus, myopathy is usually associated with such "segmental necrosis", with some of the surviving segments being functionally cut off from their nerve supply via loss of continuity with the neuromuscular junction. The multinucleated arrangement is important in pathologic states such as myopathy, where focal necrosis (death) of a portion of a skeletal muscle fiber does not result in necrosis of the adjacent sections of that same skeletal muscle fiber, because those adjacent sections have their own nuclear material.
Large skeletal muscle fibers form by the fusion of thousands of individual muscle cells. Most fungi of Basidiomycota exist as a dikaryon in which thread-like cells of the mycelium are partially partitioned into segments each containing two differing nuclei, called a heterokaryon.Īnimals Skeletal muscle Ī classic example of a syncytium is the formation of skeletal muscle. The " nucellar plasmodium" of the family Podostemaceae Ī syncytium is the normal cell structure for many fungi.Some examples of plant syncytia, which result during plant development, include: In protists, syncytia can be found in some rhizarians (e.g., chlorarachniophytes, plasmodiophorids, haplosporidians) and acellular slime moulds, dictyostelids ( amoebozoans), acrasids ( Excavata) and Haplozoon.