Reproduction III

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Reproduction III

Lecture number:
Lecture Note
University of Southern California
Bisc 307l - General Physiology
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BISC 307L 1st Edition Lecture 22 Current Lecture  The Placenta o o Early embryo burrows its way into the blastocyst tissue which has finger like projections called chorionic villae and as it goes it destroys the tissue and nourishesthis causes bleeding which doesn’t clot because the chorionic villae produces anticoagulantspools of blood that the blastocyst tissue is invading and this causes the exchanging of blood between the embryo and the motherdevelops the circulatory system which develops partly into placenta o Maternal blood is bleeding into these spacesexchange of nutrients across the placenta o Exception to the rule that vertebrates have a closed circulatory system o Chorion secretes chorionic gonadotropin which prolongs the life of the corpus luteum (mimics LH) o Essential in the first 2 months o BY the 3rd month the placenta itself starts secreting progesterone and estrogen but the first two months rely on the corpus luteum

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