neurulaandmesoderm神经轴胚和中胚叶.pptVIP

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * Neurula and Mesoderm Jian Luo Development of a human embryo from fertilization to implantation Migration of endodermal and mesodermal cells through the primitive streak Primary neurulation: neural tube formation in the chick embryo Three views of neurulation in an amphibian embryo Comparison of mesodermal development in frog and chick embryos The major lineages of the mesoderm Neural tube and somites Nature Volume 423 Number 6937, 15 May 2003 The skeleton background Three distinct lineages: The somites generate the axial skeleton, the lateral plate mesoderm generates the limb skeleton, and the cranial neural crest gives rise to the branchial arch and craniofacial bones and cartilage. Two tissues: bone and cartilage Three cell types: chondrocytes, osteoblasts and osteoclasts Bone formation Intramembranous bone formation (Mesenchymal cells form condensations, then differentiate into bone-forming osteoblasts) e.g. flat bone (skull, part of clavicle) Endochondral bone formation Most of bone formation belong to this formation Bone Homeostasis Between Osteoblast Produce Bone and Osteoclast Absorb Bone osteoblast osteoclast Neural crest cell migration in the trunk of the chick embryo Cranial neural crest cell migration in the mammalian head Histological Analyses of Calvariae Histomorphometric Analysis of Vetrebra Key stages in limb skeletal development 肢体细胞的来源肌肉细胞前体：来源于体节的轴下生肌区；骨细胞前体：侧板中胚层的体细胞区间质细胞。 肢芽的形成受来自于中间中胚层(intermediate mesoderm)如肾前体的信号诱导，移去中肾或在中肾与肢芽细胞间插入不透膜可使肢芽停止增大。 Signalling centers in the limb bud Two models for proximodistal limb skeletal patterning Endochondral bone formation Skeletal development Differentiation factors in chondrocytic and osteoblastic differentiation Indian hedgehog (Ihh)/parathyroid hormone-related protein (PTHrP) negative feedback loop Osteoclastogenesis Hormonal control of bone resorption RANK signalling network in oste