Limb bud

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Limb bud
Days	29
Precursor	lateral plate mesoderm

In embryology, the limb bud is a structure formed by the developing limb, derived from lateral plate mesoderm^{[citation needed]}. It is intimately related with the apical ectodermal ridge, which secretes factors (fibroblast growth factors for example) inducing the initial differentiation of the limb bud. In turn, the mesodermal tissue of the limb bud secretes factors sustaining the development of the Apical Ectodermal Ridge.

v • d • e Developmental biology > Human embryogenesis (development of embryo) and development of fetus (some dates are approximate - see Carnegie stages and a timeline) Week 1 Fertilization - Egg activation - Zygote - Cleavage - Morula - Blastula (Blastomere) - Blastocyst - Inner cell mass Week 2 Bilaminar disc (Hypoblast, Epiblast) Week 3 (Trilaminar embryo, germ layers) Archenteron/Primitive streak (Primitive pit, Primitive knot/Blastopore, Primitive groove) - Gastrula/Gastrulation - Regional specification Ectoderm: Surface ectoderm - Neuroectoderm - Somatopleure - Neurulation - Neural crest Endoderm: Splanchnopleure Mesoderm: Chorda- - Paraxial (Somite/Somitomere/Sclerotome/Myotome/Dermatome) - Intermediate - Lateral plate (Intraembryonic coelom, Splanchnopleure/Somatopleure) Extraembryonic/uterus Trophoblast (Cytotrophoblast, Syncytiotrophoblast) Blastocoele - Yolk sack/exocoelomic cavity - Heuser's membrane - Extraembryonic coelom - Vitelline duct Umbilical cord (Umbilical artery, Umbilical vein, Wharton's jelly) - Allantois Placenta - Decidua (Decidual cells) - Chorionic villi/Intervillous space - Gestational sac (Amnion/Amniotic sac/Amniotic cavity, Chorion) Histogenesis Programmed cell death - Stem cells - Germ line development Organogenesis Limb development: Limb bud - Apical ectodermal ridge/AER other structures: Eye development - Cutaneous structure development - Heart development - Development of the urinary and reproductive organs