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Gastrulation

Gastrulation. Outline. Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 References. Outline. Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9

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Gastrulation

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  1. Gastrulation

  2. Outline Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 References

  3. Outline Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 References

  4. Gastrulation Gastrulation is a phase early in the embryonic development of most animals, during which the single-layered blastula is reorganized into a multilayered structure known as the gastrula.

  5. Gastrulation Before gastrulation, the embryo is a continuous epithelial sheet of cells; by the end of gastrulation, the embryo has begun differentiation to establish distinct cell lineages, set up the basic axes of the body (e.g. dorsal-ventral, anterior-posterior), and internalized one or more cell types including the prospective gut.

  6. Outline Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 References

  7. Gastrulation by week Gastrulation is the conversion of the epiblast from a bilaminar disc into a trilaminar embryonic disc consisting of ectoderm, mesoderm, and endoderm. It is begins in week 3and finish in week 8 of pregnancy

  8. Gastrulation by week • Week 1-2: no developments occurs fertilization has not actually occurred.

  9. Week 3 • Week 3: from 15-21 days, embryonic 5-7 days. • Fertilization occur and form zygote. • The embryo hatches from its protein shell and perform implantation (5-6 days).

  10. Outline Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 References

  11. Week 4 • Week 4 – days 22-28 (embryonic age 2 weeks) • Trophoblast cells surrounding embryonic cells proliferate and invade deeper into uterine lining. • Eventually form placenta and embryonic membrane. • Formation of yolk sac. • Primitive streak develop at 13 days. • Primary stem villi appears at 13 days.

  12. Week 4

  13. Outline Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 References

  14. Week 5 • Week 5 (gestational age = 4 weeks) • (embryonic age = 3 weeks) • A notochord forms in the center of the embryonic disk • Gastrulating commences.(day 16 for fert.) • A neural groove (future spinal cord) forms over the notochord with a brain bulge at one end, neuromeres appear. • Somites , the divisions of the future vertebra, form. • Primitive heart tube is forming, vasculature begins to develop in embryonic disc.

  15. Week 5

  16. Outline Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 References

  17. Week 6 • Week 6 (gestational age 5 weeks) • (embryonic age 4 weeks) • Embryo measures 4 mm • The heart bulge, begins to beat in a regular rhythem . • The neural tube closes. Arm buds and tail are visible. • Pulmonary primordium appear. Hepatic plate appear. • Buccophryngeal membrane ruptures , this form the future mouth. Anterior and posterior horns differentiate in the spinal cord.

  18. Week 6

  19. Outline Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week9 References

  20. Week 7 • Week 7 (embryonic age 5 weeks) • Length is 9 mm. • Lens pits and optic cups develops. • Nasal pits form. • Brain divides into 5 vessicles including early telencephalon. • Leg buds form. • The metanphors, precursor of kidney start develop. • Stomach differentiation begins.

  21. Week 7

  22. Outline Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week9 References

  23. Week 8 • Week 8 • The embryo measures 13 mm (1\2 inch) in length. • Lungs begin to form. • The brain continues to develop. • Arms and legs have lengthened with foot and hand areas distinguishable. • The hands and feet have digits, but may still be webbed. • The gonadal ridge begins to be perceptible. • The lymphatic system begins to develop. • Main development of external genitalia starts.

  24. Week 8

  25. Outline Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 References

  26. Week 9 • Week 9 • The embryo measures 18 mm(3\4 inch) in length. • Fetal heart tone (the sound of the heart beat) can be heard usind Doppler. • Nipples and hair follicles begin to form. • Location of the elbows and toes are visible. • Spontaneous limb movements may be detected by ultrasound. • All essential organs have at least begun. • The vitelline duct normally closes.

  27. Week 9

  28. Outline Definition of Gastrulation Gastrulation by pregnancy’s week Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 References

  29. References www.presentationszone.com www.dreamstime.com www.homeopathienetwerk.nl www.en.wikipedia.org http://americanpregnancy.org/ http://pimeonline.blogspot.com/ www.parentingpatch.com

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