placental barrier


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Related to placental barrier: Blood brain barrier

barrier

 [bar´e-er]
1. an obstruction.
2. a partition between two fluid compartments in the body.
3. a covering used to prevent contact with body fluids.
alveolar-capillary barrier (alveolocapillary barrier) see under membrane.
blood-air barrier alveolocapillary membrane.
blood-aqueous barrier the physiologic mechanism that prevents exchange of materials between the chambers of the eye and the blood.
blood-brain barrier see blood-brain barrier.
blood-gas barrier alveolocapillary membrane.
blood-testis barrier a barrier separating the blood from the seminiferous tubules, consisting of special junctional complexes between adjacent Sertoli cells near the base of the seminiferous epithelium.
barrier methods contraceptive methods such as condoms and diaphragms in which a plastic or rubber barrier blocks passage of spermatozoa through the vagina or cervix. See discussion under contraception.
placental barrier the tissue layers of the placenta which regulate the exchange of substances between the fetal and maternal circulation.

pla·cen·tal mem·brane

the semipermeable layer of fetal tissue separating the maternal from the fetal blood in the placenta; composed of: 1) endothelium of the fetal vessels in the chorionic villi, 2) stromata of the villi, 3) cytotrophoblast (negligible after the fifth month of gestation), and 4) syncytiotrophoblast covering the villi; the placental membrane acts as a selective membrane regulating passage of substances from the maternal to the fetal blood.
Synonym(s): placental barrier

pla·cen·tal mem·brane

(plă-sen'tăl mem'brān)
The semipermeable layer of fetal tissue separating the maternal from the fetal blood in the placenta; composed of: 1) endothelium of the fetal tissues in the chorionic villi, 2) stromata of the villi, 3) cytotrophoblast (negligible after the fifth month of gestation), and 4) syncytiotrophoblast covering the villi; the placental membrane acts as a selective membrane regulating passage of substances from the maternal to the fetal blood.
Synonym(s): placental barrier.

placental

pertaining to or emanating from placenta.

placental barrier
the placental separation of maternal and fetal blood which varies in its structure and permeability between the species. In general the more layers of cells between the two circulations the less permeable the membrane. In none of the domestic animals are significant amounts of immune globulins or erythrocyte antigens passed through the membranes unless the epithelium is damaged. See also placenta.
placental calcification
accumulations of mineral deposit especially around the vessels and in the allantois, a normal occurrence in most species.
placental cavities
the allantoic and amniotic cavities; called also amniotic and allantoic sac.
placental edema
edema of the placenta, without necessarily any involvement of the fetus.
placental hormones
the placenta in all species produces estrogens and progesterone. In the cow it also produces lactogen, a hormone that influences structural and functional aspects of milk production. In the mare the endometrial cups produce pmsg (now called eCG) which assists in the maintenance of pregnancy. The equine, feline and primate placentae also produce relaxin which has a similar action.
placental implantation
the placenta of a viable fetus, escaped from the genital tract, can implant successfully to the peritoneum.
placental inflammation
placental lactogen
a placental hormone present in the cow's peripheral circulation at about 160 days of pregnancy; thought to have prolactin and growth-hormone capabilities.
placental mole
see mole.
placental plaques
are normal structures on the amnion in most species. They are foci of squamous epithelium.
placental removal
manual removal per vagina, detaching the placenta from each caruncle in turn.
placental transfer of immunoglobulins
see placental barrier (above) and passive immunity.
References in periodicals archive ?
beta]-hCG release is a marker of continuous endocrine activity of the syncytiotrophoblast, the epithelial layer of chorionic villi forming the placental barrier (Miller et al.
Alcohol passes easily through placental barrier and, because the foetus is less equipped to break down alcohol than its mother, it receives a high concentration of alcohol.
SAN FRANCISCO -- Hydroxychloroquine to treat rheumatic disease seemed safe in a retrospective study of 60 pregnancies, but a separate study found that the drug does cross the placental barrier to the fetus.
In sows, "it crossed the placental barrier and directly infected the fetus," Kirkland says.
I believed that something crossed the placental barrier when I was in gestation with Colette.
OBJECTIVE: In this study we investigated whether particles can cross the placental barrier and affect the fetus.
Earlier tests in animals had shown that chemicals inhaled by pregnant rodents can cross the placental barrier to damage their young.