chorionic

chorionic [kor″e-on´ik]

pertaining to the chorion.

chorionic villi numerous branching projections from the external surface of the chorion that provide for exchange between the maternal and fetal circulation. Oxygen and nutrients in the maternal blood diffuse through the walls of the villi and enter the blood of the embryo or fetus. Carbon dioxide and waste products diffuse from blood in the fetal capillaries through the walls of the villi into the maternal blood. See also chorionic villus sampling.

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chorionic

pertaining to the chorion.

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chorionic girdle

a circular band of cells of placental origin that invade the endometrium and form the endometrial cups in the mare.

chorionic girdle cells

see chorionic girdle (above).

chorionic gonadotropin

a hormone with properties similar to those of luteinizing hormone; it is secreted in large amounts by the placenta during gestation. It stimulates the formation of interstitial cells in the testes of the fetus and causes the secretion of testosterone. It is found in substantial amounts in the urine of pregnant mares (pregnant mares serum gonadotropin—PMSG) and pregnant women (human chorionic gonadotropin—HCG). It is used as an aid in the treatments to induce ovulation and the synchronization of estrus.

chorionic somatomammotropin

see placental lactogen.

chorionic vesicle

the early embryonic vesicle before the allantois has developed and encircled the embryo to form the chorioallantoic vesicle and supplant it.