What is ectomesenchyme?
Filters. (anatomy) A form of mesenchyme, in the embryo, consisting of neural crest cells; forms the tissues of the neck and cranium.
How is ectomesenchyme formed?
The origin of the ectomesenchyme is disputed. It is either like the mesenchyme, arising from mesodermic cells, or conversely arising from neural crest cells. The neural crest is a critical group of cells that form in the cranial region during early vertebrate development.
What structures are derived from the ectomesenchyme?
Ectomesenchymal derivatives include bone, cartilage, connective tissue and dentine, while the non-ectomesenchymal derivatives consist of neurons, glia and pigment cells (Le Douarin and Kalcheim, 1999; Graham, 2003).
What is the difference between mesenchyme and ectomesenchyme?
The key difference between mesenchyme and ectomesenchyme depends on the type of cells they contain. Mesenchyme contains loose cells that migrate easily to form the ground tissue of collagen, and bone and cartilage tissue while ectomesenchyme contains neural crest cells and forms the tissues of neck and cranium.
What is ectomesenchyme condensation?
At this point, the tooth bud grows around the ectomesenchymal aggregation, taking on the appearance of a cap, and becomes the enamel (or dental) organ covering the dental papilla. A condensation of ectomesenchymal cells called the dental sac or follicle surrounds the enamel organ and limits the dental papilla.
Is the dental follicle from ectomesenchyme?
The dental follicle is a loose ectomesenchyme-derived connective tissue surrounding the enamel organ and the dental papilla of the developing tooth germ before eruption.
When the embryo is 5 to 6 weeks old the first signs of tooth development are found in the?
Initiation Stage. One of the earliest signs in the formation of a tooth that can be seen microscopically is the distinction between the vestibular lamina and the dental lamina. It occurs in the sixth to seventh week of the embryonic life.
Where does the mesoderm come from?
The mesoderm is a germ layer that arises during gastrulation, and is present between the ectoderm, which will turn into skin and central nervous system cells, and the endoderm, which will produce the gut and the lungs (4).
What are the stages of odontogenesis?
The continuous and progressive stages of odontogenesis have classically been divided into the dental lamina, bud, cap and bell stages, root formation and tooth eruption.