Windshield Presentation Grading Criteria on the student website. Identify lessons for the future that can be learned from past public health experiences.
The placenta synthesizes and secretes steroid and peptide hormones that regulate hormonogenesis by endocrine glands in both the mother and the fetus.
Moreover, the placenta metabolizes the large quantities of steroid hormones produced by the maternal endocrine glands to protect the fetus and to orchestrate the timing and development of fetal organ systems, the fetal pituitary-adrenocortical axis in particular.
Clearly, placental hormonogenesis and metabolism are among the most important determinants of a successful pregnancy; however, despite the numerous advances in our understanding of placental-fetal function, our knowledge of the factors acting and interacting to regulate these processes during human pregnancy remains incomplete.
The purpose of this chapter is to review the classic and more recent concepts regarding: Because the study of maternal-fetal-placental function during human pregnancy is necessarily limited by ethical constraints, this chapter draws heavily on relevant information derived from in vivo experiments conducted in nonhuman primate models.
Finally, because of its broad scope, this chapter provides a more general review, rather than an in-depth analysis, of the factors important to pregnancy maintenance, parturition, and fetal development. More in-depth reviews of key aspects of placental and fetal adrenocortical-gonadal development have recently been published.
Enders 3233 has concluded that prior to attachment to the uterine epithelium, mononucleated cytotrophoblast cells of the trophectoderm fuse to form a syncytiotrophoblast layer.
The syncytiotrophoblast appears to initially interact with and adhere to the endometrium. Only after the embryo is totally embedded in the endometrium do cytotrophoblast cells begin to move from the trophoblastic shell to invade the uterus and the uterine vasculature.
The human preimplantation blastocyst 5 days after conception. The innercell mass, the cells destined to form embryonic structures, is seen between 3 and 6 o'clock. The remainder consists of the trophectoderm. Biologic and morphologic development of donated human ova recovered by nonsurgical uterine lavage.
Am J Obstet Gynecol In virtually all mammals, preparation of the uterus for implantation is regulated by the coordinated actions of estrogen and progesterone 37 produced and secreted by the ovary-corpus luteum and perhaps by the developing embryo itself. During this interval, and presumably under the influence of estrogen and progesterone, the uterine endometrium is thickened and highly secretory in nature and becomes rich in glycogen and lipids.
Changes in the composition of the uterine glycocalyx have also been observed during the peri-implantation period.
For example, the levels of two transmembrane glycoproteins, mucin MUC-1 and keratan sulfate, increase on the endometrial glandular surface during the early luteal phase, 94748 then decrease as the window for implantation opens.
Epithelial integrins have been proposed as markers for the window of implantation in the human. A similar distribution of endometrial integrins and extracellular matrix proteins has been described across the menstrual cycle and early pregnancy in the baboon.
A similar role for LIF in humans and nonhuman primates has not been confirmed. Growth factors and their receptors in human endometrium during the menstrual cycle.
Tissue levels shown are relative to the proliferative phase of the cycle. Giudice LC, Saleh W: Growth factors in reproduction. Trends Endocrinol Metab 6: Almost immediately after fertilization, the embryo secretes platelet-activating factor PAFinterleukins-1 and -6, and early pregnancy factor.
Although inhibition of PAF activity in vivo prevented implantation in rodents, 60 a similar role in primate pregnancy has not been demonstrated. By the 8-cell stage, the blastocyst apparently secretes a number of cytokines and growth factors including chorionic gonadotropin hCGlong recognized as one embryonic factor that is essential for early pregnancy in primate species.
The high levels of hCG secreted into the maternal circulation during early gestation apparently are sufficient to bind to the thyroid-stimulating hormone TSH receptor and thereby to increase maternal thyroid hormone production.
Although the physiologic role of most of these factors remains to be defined, CRH may play a role in parturition, 7677 modulation of uterine blood flow, 78 and regulation of maternal pituitary ACTH production.
Mean serum hCG levels throughout normal pregnancy: Arithmetic scale used on ordinate. Serum human chorionic gonadotropin levels throughout normal pregnancy. Current perspective on the endocrine and local mechanisms activated during rescue of the corpus luteum at the start of pregnancy in primate species.
Solid lines indicate established pathways, whereas dotted lines indicate proposed pathways. Embryo-derived hCG, perhaps regulated by locally produced GnRH or other factors, prevents the typical regression of the corpus luteum at the end of the nonfertile ovarian cycle.
Therefore, the corpus luteum continues to produce progesterone, which sustains intrauterine pregnancy until the luteal-placenta shift. Embryo-maternal interactions during the establishment of pregnancy in primates.
In Charlton HM [eds]: Oxford Reviews of Reproduction Biology. Oxford, Oxford University Press, Fig. The steroid biosynthetic pathway for the conversion of substrate cholesterol to the progestogens, androgens, and estrogens.
Placental steroidogenesis in primate pregnancy.Hcs Week 3 Team Assignment Peri Model Resource Grading Criteria On The Student Website Review And Process Described In Ch 2 Of Text Complete Each Following Steps.
HCS is a online tutorial store we provides HCS Week 3 Team Assignment PERI Model. Fukuoka | Japan Fukuoka | Japan. For more course tutorials visit kaja-net.com Learning Team Assignment: PERI Model • Resource: PERI Model Grading Criteria on the student website.
• Review the PERI model and process described in Ch. 2 of the text. • Complete each of the following steps using the public health issue or disease your team got approval for last week: o .
View Homework Help - Week 3 Team Assignment from HCS at University of Phoenix. DIABETES AND THE P.E.R.I.E. MODEL March 14, HSC/ Rachaline Napier P.E.R.I.E. MODEL Problem: What is the%(20).
hcs/ Deana Halat Socioeconomic contributions to the disease Identify the underlying nature and cause of HIV Correlation between community,state and national levels Possible solutions Effectivness of Solutions Additional Suggestions Using the PERI Model for guidence Underlying Causes of HIV Socioeconomic Status.