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One theory is that velamentous cord insertion may arise from the process of placental trophotropism, which is the phenomenon where the placenta migrates towards areas which have better blood flow with advancing gestation. The placenta grows in regions with better blood supply and portions atrophy in regions of poor blood flow.
In Type 2, unprotected vessels run between lobes of a bilobed or succenturiate lobed placenta. In Type 3, a portion of the placenta overlying the cervix undergoes atrophy. In this type, there is a normal placental cord insertion and the placenta has only one lobe. However, vessels at a margin of the placenta are exposed.
The vasculature of the body-stalk develops into umbilical arteries that carry deoxygenated blood to the placenta. [12] It is externally continuous with the proctodeum and internally continuous with the cloaca. The embryonic allantois becomes the fetal urachus, which connects the fetal bladder (developed from cloaca) to the yolk sac.
The placenta (pl.: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation.It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important endocrine organ, producing hormones that regulate both maternal and fetal ...
Placental pathology (velamentous insertion, succenturiate lobes, bipartite i.e. bilobed placenta etc.) [13] Baby is in an unusual position: breech (buttocks first) or transverse (lying horizontally across the womb). Placenta previa is itself a risk factor of placenta accreta. Alcohol use during pregnancy was previously listed as a risk factor ...
The placenta can be defined as an organ formed by the sustained apposition or fusion of fetal membranes and parental tissue for physiological exchange. [1] This definition is modified from the original Mossman (1937) [2] definition, which constrained placentation in animals to only those instances where it occurred in the uterus.
Also gastrocoel. The central internal cavity of the gastrula in most animal embryos, fated to develop into the lumen of the digestive tube ; the primitive gut. The archenteron initially has only one open end, known as the blastopore. B birth blastocoel Also blastocoele, blastocele, cleavage cavity, and segmentation cavity. The fluid-filled or yolk -filled cavity that forms in the developing ...
A conceptus (from Latin: concipere, to conceive) is an embryo and its appendages (adnexa), the associated membranes, placenta, and umbilical cord; the products of conception [1] or, more broadly, "the product of conception at any point between fertilization and birth."