Fertilization and Development

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Fertilization and Development

• So thats what happens after! ?

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Fertilization

• DAY 0
• When sperm penetrates egg
• Sperm releases special enzymes to do this
• Forms a ZYGOTE FERTILIZATION OCCURS
• Recombination occurs
• Combining of genetic info from both parents
• Occurs in Fallopian tube

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Early Development- The First Week

• Zygote begins to divide, divide, divide
• UNDERGOING MITOSIS!!!!!!!
• Hopping along the Fallopian Tube trail!
• Implantation of zygote in uterus
• Occurs around day 7

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Trail of an Embryo
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Close up look at embryo changes
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Early Development- Gastrulation

• Cells in zygote form into 3 distinct layers
• Endoderm
• Digestive and other inner organs
• Mesoderm
• Circulatory
• Ectoderm
• Nervous
• Skin
• The cells within each layer will DIFFERENTIATE
  MITOSIS!!!!
• Become different (skin cells, heart cells, etc.)

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Early Development- Gastrulation
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OVERVIEW OF EARLY DEVELOMENT
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Overview of Early DevelopmentStage 1-
Fertilization
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Overview of Early DevelopmentStage 2- Zygote
Formation
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Overview of Early DevelopmentStage 3 4
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Overview of Early DevelopmentStage 5
Gastrulation
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The Placenta
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The Role of the Placenta

• Develops at 3 weeks
• Placenta is a fetal organ
• Connects mother and fetus
• PLACE OF
• RESPIRATION (GAS EXCHANGE)
• NOURISHMENT (GETTING NUTRIENTS)
• EXCRETION (RID OF WASTES)

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First and Second Trimester Dangers!!!!

• Critical Development stage
• Drugs, alcohol, and medicines can severely damage
  embryo/fetus
• This can halt development or cause major
  developmental issues
• Not taking care can result in miscarriage or
  severe deformities of child

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Later Development

• 8 weeks FETUS
• Umbilical cord fully formed at 3 months (12
  weeks)
• Body systems become more specialized
• Fetus becomes bigger
• Total human gestation period about 40 weeks
  (full term at 37 weeks)

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Cool Website!

• http//www.ehd.org/movies-index.php