FORMATION AND ROLE OF THE PLACENTA
1.  Preparation of the uterus
  Window of receptivity

2.  Implantation (nidation)
Apposition, Adhesion
Penetration of endometrial epithelium
Invasion of decidua

3.Establishment of a hemochorial placenta
     Lacunar
Development of chorionic villi
           Intervillous
         Maternal plasma only
         Whole blood
1.E is proliferative reaches high levels, positive feedback LH and FSH surge, ovulation, P secretory, window of receptivity, pinopods, endometrium mucus covered, LIF (IL-6 cytokine) , sticky integrins,  glycogen
2. Barrier and how overcome.  Clues to infertility, spontaneous (undetected) abortions and ART
3. Chorion development
    Final product