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Fertilization
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Begins to exist when sperm reaches the egg
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Pronuclei join together
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Occurs when the 23 male chromosomes join the 23 female chromosomes
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Second round of mitosis
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Third round of mitosis
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after 3rd round of mitosis
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Occurs when 3rd cleavage happens
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64 cell embryo called a blastocyst
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Happens after compaction, day 5-7
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Ectopic pregnancy could occur during implantation
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Implantation
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Disc with streak on the underside forms mesoderm
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HCG begins to be secreted
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First missed period
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Neural tube forms
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Heart begins to beat, arm & leg buds appear, yolk sac makes RBCs
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Face plates forming
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Cleft lip or palate may occur
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Muscles form, bent neck, webbed hands and feet, segmented back
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Fingers & toes separate, eyes & ears formed
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Occurs when all organs are formed, day 49
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Genitalia begins to differentiate, eyelids fuse, amnion surrounds fetus
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Eyes open, fat added under skin, head out of proportion to the body
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Chorionic villi sampling could be performed
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Amniocentesis could be performed
