Embryology: Implantation

Implantation

 Implantation is the embedding of the embryo in the uterine lining. 

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   Placenta

  • Exchange place or maternal and fetal circulation 

Functions of the placenta

  • Gas and nutrient exchange 
  • Antibodies 
      * Proactive proteins made by immune system
      * Protect fetus

Components of placenta

Decidua- maternal part of placenta

  • Forms from endometrium
  • Decidual reaction- endometrial changes due to implantation

Chorion-fetal part of placenta

  • Forms from trophoblast 
  • Chorionic villi- extensions of chorion
      * EXCHANGES BETWEEN MATERNAL AND FETAL BLOOD OCCUR HERE

HCG

  • Human Chorionic Gonadotropin
      * Produced by developing placenta
        * Can be detected in pregnancy tests  
        * Embryo is attaching to uterine lining 

Dominant definition of conception and pregnancy is based on the moment of fertilization 

Ectopic Pregnancy

  • An implantation in an abnormal area
      * Most common in uterine tubes
        * Growth of embryo can cause tubes to burst
        * Blood loss can be fatal 

   Causes of Ectopic Pregnancy:

  • Slowed transport
      * Cilla problems
        * Slow transport
      * Sexually transmitted diseases
        * Scar uterine tissue
      * Endometriosis
        * Endometrium like tissue in abnormal areas
        * Promote uterine tube scarring
        * Provide Abnormal areas of easy implantation

Treatment of Ectopic Pregnancy:

  • Expectant management 
      * Close observations with interventions only when symptoms manifest
  • Salpingectomy 
      * Removing uterine tube containing embryo
  • Salpingostomy 
      * Removal of embryo
  • Methotrexate 
      * A drug that prevents cell division and growth
  • Embryo transfer
      * Transfer of embryo to womb

Regulative development- ability to produce normal structures if cells are removed or added

  • Decreases as development progresses 
  • Blastomere isolation
      * Single blastomeres can form normal embryos
        * Up to 4 cell stage

Chimera- an organism with a mixture of cells from two individuals 

Tetraparental embryo- embryo with 4 genetic parents

Fetal microchimerism- the presence of fetal cells in the mother

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