Embryo

Human Fetal Development

By lpolhamus
  • Start

    Start

    Fertilization

  • Fertilized Egg

  • 12 hours

    12 hours

    pronuclei join together

  • Zygote Stage Begins

  • 30 - 36 Hours

    30 - 36 Hours

    first round of mitosis [cleavage]
  • 40 Hours

    40 Hours

    second round of mitosis
  • 50-60 Hours

    50-60 Hours

    third round of mitosis
  • Morula Formed

    Morula Formed

  • Ectopic Pregnancy Could Occur

    Ectopic Pregnancy Could Occur

  • Day 4

    Day 4

    64 cell embryo called a blastocyst
  • Hatching

    Hatching

  • Embryonic Period Begins

  • Day 10

    Day 10

    Implantation

  • hCG begins to be secreted

  • Day 15

    First Missed Period
  • Day 21

    Day 21

    disc with streak on the underside forms mesoderm
  • Day 22

    Day 22

    Heart begins to beat, arm & leg buds appear, yolk sac makes RBCs
  • Day 28

    Day 28

    Neural tube forms
  • Days 34, 35 & 36

    Days 34, 35 & 36

    Face plates come together
  • Cleft Lip or Palate may occur

    Cleft Lip or Palate may occur

  • 6th Week

    6th Week

    muscles form, bent neck, webbed hands and feet, segmented back
  • 7 Weeks

    7 Weeks

    fingers & toes separate, eyes & ears are formed
  • Fetal Period begins

    Fetal Period begins

  • Day 50

    Day 50

    genitalia begins to differentiate, eyelids fuse, amnion surrounds fetus
  • 9-11 Weeks

    9-11 Weeks

    chorionic villi sampling could be performed
  • 14-15 Weeks

    14-15 Weeks

    amniocentesis could be performed
  • 6 Months

    6 Months

    eyes open, fat added under skin, head out of proportion to the body