BIOL130 Lecture Notes - Somatopleuric Mesenchyme, Gastrointestinal Tract, Mothers Against Decapentaplegic Homolog 2
28 Jan 2013
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Gastulalation: epiblast cells move through a structure, forming layers. Starts 2 weeks after fertilization, and takes 2 more weeks to finish. 2) 3 germ layers (ecto, meso, endo) (endo moves through first) Made up of a constantly changing/moving cell population (epithelium mesenchymal) Neural plate folds on itself into the neural tube. Neural crest = junction of se and nt. **both have signaling roles during development but don"t contribute to much later on in adulthood (nuclei pulposi)** Begins as a continuous cord of cells on either side of notochord. Somites subdivide sclerotomes + dermamyotome (vertebral, ribs, sternum, clavicle) (skin, musc. ) Ventral splanchnic splanchnopleuere gut tube, mesentery. Curls on itself to make lining of gut tube, buds off in places for organs (thyroid, lungs, liver, pancreas) Never forms as a part of the mature organism. Nutritive/ supportive role for embryo; necessary for gastrulation. 1) nodal expressed by epiblast (induced by extraembryonic signals) 2) nodal positively self-regulates spreads throughout epiblast, ve.
