Osmotr Anesteziologa Blank
воскресенье 04 ноября admin 18
Contents • • • • • • Structure [ ] Odontoblasts are large columnar cells, whose cell bodies are arranged along the interface between dentin and pulp, from the crown to cervix to the root apex in a mature tooth. The cell is rich in and Golgi complex, especially during primary dentin formation, which allows it to have a high secretory capacity; it first forms the collagenous matrix to form predentin, then mineral levels to form the mature dentin. Odontoblasts form approximately 4 μm of predentin daily during tooth development. During secretion after differentiation from the outer cells of the dental papilla, it is noted that it is polarized so its nucleus is aligned away from the newly formed dentin, with its Golgi complex and endoplasmic reticulum towards the dentin reflecting its unidirectional secretion. Thus with the formation of primary dentin, the cell moves pulpally, away from the basement membrane (future dentinoenamel junction) at the interface between the inner enamel epithelium and dental papilla, leaving behind the odontoblastic process within the pulp. The odontoblastic cell body keeps its tapered structure with cytoskeletal fibres, mainly.
Unlike cartilage and bone, as well as cementum, the odontoblast’s cell body does not become entrapped in the product; rather, one long, cytoplasmic attached extension remains behind in the formed dentin. The differentiation of the odontoblast is done by signaling molecules and growth factors in the cells of the inner enamel epithelium. Like enamel, dentin is avascular. Nutrition for odontoblasts within the dentin comes through the dentinal tubules from tissue fluid that originally traveled from the blood vessels located in the adjacent pulp tissue. Within each dentinal tubule is a space of variable size containing dentinal fluid, an odontoblastic process, and possibly an afferent axon (see next discussion). The dentinal fluid in the tubule presumably also includes the tissue fluid surrounding the cell membrane of the odontoblast, which is continuous from the cell body in the pulp.
-meditsinskij-osmotr-blank-prikaz-302-ot-12-/ 2018-03-04 weekly. ToriBell 11.11.16 15:31 comment3, chity_na_blokadu.
It has been shown that odontoblasts secrete the protein. A pulpal A-delta (noxious, short sharp pain) nerve fibre is either wrapped around the base of this process, or travels a short way into the dentinal tubule with the odontoblast process (max ~0.1 mm) This process lies in the dentinal tubule. Adobeacrobat70professional inclkeygen paradox. In an erupted tooth, this process rarely extends beyond 1/3 the depth of the dentin, which is why the odontoblast transduction theory of dentinal hypersensivity is unlikely.
Development [ ] Odontoblasts first appear at sites of tooth development at 17–18 weeks and remain present until death unless killed by bacterial or chemical attack, or indirectly through other means such as heat or trauma (e.g. During dental procedures). Odontoblasts were originally the outer cells of the dental papilla. Thus, dentin and pulp tissue have similar embryological backgrounds, because both are originally derived from the dental papilla of the tooth germ.