Zygote to Implantation

The zygote begins to divide rapidly in the fallopian tube. 
  • Early-Stage Human Pregnancy | Medical Science Navigator
  1. 2.  Implantation (Week 2):
    • The zygote, now a morula, travels to the uterus. 
    • The morula develops into a blastocyst and implants in the uterine lining. 
  2. 3.  Gastrulation and Neurulation (Weeks 3-5):
    • The embryo begins to differentiate into three layers (ectoderm, mesoderm, and endoderm). 
    • The neural tube, which develops into the brain and spinal cord, forms. 
    • The heart and major blood vessels develop early. 
    • The heart starts beating around 5 weeks. 
  3. 4.  Organogenesis (Weeks 5-8):
    • Most major organs and systems take shape. 
    • Limb buds form, eventually developing into arms and legs. 
    • Facial features begin to develop. 
    • The embryo's head becomes disproportionately large compared to the rest of the body. 
  4. 5.  End of the Embryonic Period (Week 8):
    • The embryo is approximately 3 cm (1.2 inches) from crown to rump and weighs about 8 grams. 
    • The embryo is now considered a fetus, and fetal development continues until birth. 

 

 

 

Zygote to Implantation

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