ABSTRACT
I. Introduction ............................................................................................................... 1 07
III. Opioid Peptides ......................................................................................................... 113 A. Overview ............................................................................................................. 113 B. Presence in Human Placenta .............................................................................. 113
C. Correlations between Opioid Receptors and Peptide Levels with Mode of Delivery ................................................................................................ 121
Villous Tissue ..................................................................................................... 124
VI. Summary and Discussion .......................................................................................... 125
References ........................................................................................................................... 127
The anatomical localization of the human placenta separates fetal and maternal circulatory systems. Human placenta is discoid in shape and at term is approximately 20 em in diameter, reaching around 600 g of weight; it contains a highly convoluted microvillous membrane with a surface area of 10 rn2 :4 The latter allows maximum contact between maternal and fetal circulations, thus facilitating the functions mentioned above.
