DOH253 Lecture Notes - Lecture 2: Pharyngeal Groove, Tympanic Cavity, Branchial Arch
Document Summary
Ectoderm mesoderm endoderm - three germ levels of embryo. Septum transversum developing heart oropharyngeal membrane neural plate neural tube. Neural plate rapid growth reverses sequence. Neural groove deepens and separated from ectoderm covering and becomes. Some tissues at crest of neural groove called neural crest cells. As the groove deepens the tissues are separated/pinched off and travel within the mesoderm and give rise to many structures in head and neck region, particularly the cells that develop pulp, periodontal ligament, cementum and dentine. Structures of tooth other than enamel originated from the neural crest cells. Heart and liver pushed toward centre of embryo. Sequence now starts with developing brain oropharyngeal (mouth) developing heart developing liver (septum transversum) Latitudinal gives the 3d structure of the embryo. At either side of embryo paraxial mesoderm become segmented in forms of cuboidal masses called somites. Brain, mouth pushed inward, heart and liver pushed further inward.
