Reproductive system
David Sturgeon in Introduction to Anatomy and Physiology for Healthcare Students, 2018
The placenta is a temporary organ that originates from both embryonic and maternal tissue. It allows oxygen and nutrients to pass from the mother to the embryo/foetus without their blood meeting. This is important since it prevents a potential transfusion reaction from occurring (see Chapter 5). The placenta also allows waste products from the developing child, such as carbon dioxide, to pass back along the umbilical cord to the mother’s blood supply, and provides protection against bacterial infection. However, it does not protect the developing child from a number of viruses, and rubella (German measles), for example, can cause a variety of birth defects and/or miscarriage. Other potentially harmful substances that are able to cross the placenta include alcohol, nicotine and a variety of drugs and medications. The placenta is fully formed by the end of the third month of gestation and detaches from the uterus following the birth of the child at about nine months (hence it is often referred to as ‘the afterbirth’). As this book draws to a close, I can’t resist providing a final comment on the trend for eating the placenta after birth or having it ground into powder and encased in a capsule as a ‘placenta pill’ (people really do this). A quick search on the Internet revealed recipes for placenta lasagne, placenta smoothie and placenta pâté – bon appetit.
Placental origins of diabesity and the origin of preeclampsia
Moshe Hod, Lois G. Jovanovic, Gian Carlo Di Renzo, Alberto de Leiva, Oded Langer in Textbook of Diabetes and Pregnancy, 2018
The placenta is a fetal organ that early in gestation rapidly develops through a series of essential steps. These encompass Anchoring of the placenta to the maternal deciduaOpening of uterine glands to enable nutrient supply of the embryo during the first trimester of pregnancy, prior to onset of maternal blood flowSubsequent opening of spiral arteries to increase oxygen and nutrient supply to the fetus starting with the beginning of the second trimesterEstablishing villous structures and the first primitive vascular plexus within the placenta independent of vasculogenesis within the embryo proper Given the necessity to rapidly establish the uteroplacental vascular connection as well as the vasculature between embryo and placenta and because of the complex nature of the biological processes driving implantation, placentation, and embryo development, early gestation is a period of high vulnerability of both the placenta and embryo. Although tightly controlled by a variety of mechanisms, each of these processes can malfunction, which in certain situations may lead to impaired placental function later in pregnancy, which could manifest in pregnancy conditions such as preeclampsia and/or fetal growth restriction (FGR).
Placental Biosynthesis, Metabolism, and Transport of Eicosanoids
Murray D. Mitchell in Eicosanoids in Reproduction, 2020
The primary function of the placenta is to support a viable fetus throughout gestation and, as such, it serves to supply oxygen and nutrients to the fetus and remove carbon dioxide and waste products from it. As an organ of exchange, the placenta is highly vascularized, and the eicosanoids appear to play a part in the control of this vasculature. The placenta is also an extremely active endocrine organ, producing a wide variety of peptide, steroid, and other hormones, including the eicosanoids. Many of these hormones will fulfill autocrine or paracrine functions in addition to their exocrine effects. The eicosanoids are highly suitable for such functions, being potent, short-acting bioregulators. A further function of the placenta may be as an immunological barrier, serving to protect the fetal allograft from rejection. The placenta fulfills all of its functions in a remarkably short life span, during which it proliferates, matures, and achieves a variety of differentiated functions. During the lifetime of the placenta, the hormonal milieu to which its cells are subjected changes markedly as its endocrine functions change. This means that many autocrine or paracrine mechanisms may be operating within the placenta at various times to regulate eicosanoid metabolism.
Cadmium-induced preeclampsia-like phenotype in the rat is related to decreased progesterone synthesis in the placenta
Published in Xenobiotica, 2022
Xiaojie Zhang, Kai Chen, Zhu Meng, Ru Jia, Feifei Lian, Feng Lin
As is well known, the placenta plays an important role during pregnancy, which transports nutrients and oxygen to the foetus while removes of metabolic wastes and carbon dioxide from the embryos to guarantee healthy growth and development. As one of the major endocrine organs, the placenta also participates in the biosynthesis and transport of steroid hormones during pregnancy condition (Guibourdenche et al. 2009). Progesterone (P4) is a cholesterol-derived hormone critical for establishing and maintaining pregnancy and is synthesised mainly by the placenta. The rat placenta utilises maternal cholesterol as the original substrate to produce progesterone in mitochondria. There are three critical synthases in the process of progesterone production. Steroidogenic acute regulatory protein (StAR) is a rate-limiting enzyme in the transporting of cholesterol to the inner mitochondrial membrane where CYP11A1 converts it into pregnenolone. Finally, progesterone is generated from pregnenolone catalysed by 3β-HSD1 (Wu et al. 2012; Furukawa et al. 2019).
New insight into the role of long non-coding RNAs in the pathogenesis of preeclampsia
Published in Hypertension in Pregnancy, 2019
Mohammad-Taher Moradi, Zohreh Rahimi, Asad Vaisi-Raygani
Long non-coding RNA H19 (lnc-H19) is transcribed from a maternally expressed imprinted gene, which is localized on human chromosome 11p15.5 (38). This gene is composed of 5 exons and 4 introns (39). The allele-specific expression of the H19 gene in the placental tissue may result from dynamic alternations throughout the development of fetus (40). The expression of lnc-H19 is highly upregulated during mammalian embryonic development and is downregulated after birth, except in skeletal and cardiac muscle; this pattern of H19 expression suggests it is an active modulator in the development of placenta and differentiation of skeletal muscle (41). It has been reported that the lnc-H19 is downregulated in placental tissues from patients with PE (42,43). In contrast, Xu et al. declared that the lnc-H19 expression was upregulated in placental of PE patients (44). The placenta is composed of various extra-embryonic and embryonic cell lineages. The H19 gene is highly expressed by the intermediate trophoblasts and cytotrophoblasts, but low or scarcely expressed by the syncytiotrophoblasts and stromal cells in human placental samples (45,46). Therefore, different reports might be due to variation in sampling.
Umbilical artery ultrasound haemodynamics combined with serum adiponectin levels can aid in predicting adverse pregnancy outcomes in patients with severe pre-eclampsia
Published in Journal of Obstetrics and Gynaecology, 2023
Zhi Zhang, Fei Liu, Qiling Zhang, Danya Li, Liping Cai
In the present study, adverse pregnancy outcomes were defined as maternal primary postpartum haemorrhage and placental abruption, neonatal asphyxia, low birth weight, foetal distress, and foetal growth restriction (FGR) (Gottardi et al.2021, Takahashi et al.2018). Specifically, placental abruption refers to uterine bleeding greater than usual in the absence of placenta previa or trauma (related to contractions, non-reassuring foetal heart tones and/or clinical diagnosis of abruption) resulting in delivery (Tita et al. 2022). FGR represents a birth weight measuring under the 10th percentile for gestational age and infant sex according to the Duryea population standard and a small-for-gestational-age birth weight measuring under the 5th percentile (Duryea et al.2014, Tita et al.2022). Hence, this study recruited 118 sPE patients and 90 normal pregnant women and collected their clinical information and blood samples to analyse the expression of Sad and its correlation with Doppler parameters, in anticipation of predicting pregnancy outcomes in sPE patients.
Related Knowledge Centers
- Fetus
- Implantation
- Physiology
- Embryo
- Pregnancy
- Blastocyst
- Endocrine System
- Animal Embryonic Development
- Hormone
- Maternal Physiological Changes In Pregnancy