The gross anatomy of the human placenta is virtually a description of its vascular anatomy, since it is a structure almost wholly composed of fetal blood vessels which have as their main function the presentation of fetal blood to the circulating maternal blood. Pdf the human haemochorial placenta is a complex and dynamic interface between embryonic and maternal tissues. The placenta signifies the second or embryonic period of pregnancy after the implantation period and describes the establishment of a fully functional placenta. Placenta what is it and how it works biology dictionary. During human pregnancy, the placenta is an important endocrine organ. The placenta is composed of floating and anchoring chorionic villi. The function of the human placenta is of interest from both a scientific and a clinical point of view. The mature human placenta is a discoid organ 20 25 cm in diameter, 3 cm thick and weighing 400 600g internally it consists of a fetal villous tree bathed directly by maternal blood, at least during the second and third trimesters. A myriad array of compounds has been identified at this interface, some of which exert. The human placenta is a complex organ that acts as the interface between the mother and fetus. Anatomy 55 embryology 55 comparative anatomy 56 vascular architecture 56 physiology 58 barrier function 58 hormonal function 58 regulation of placental blood flow 59 transport mechanisms 59 transfer of respiratory gases and nutrients 60. Oct 14, 2014 a threepart animation depicting the development and function of the human placenta. Pathology of the human placenta kurt benirschke springer. A whitish ring composed of decidua, is seen around the placenta from its foetal surface.
Download human anatomy and physiology pdf 10th edition. The placenta consists of two equal parts connected by membranes. Formation and role of placenta columbia university. In contrast to a labyrinthine placenta, in which fetal blood streams in a variety of anastomosing structures, the villous placenta looks more like a branching tree, with fetal blood streaming centrally. The anatomy of the normal placenta request pdf researchgate.
Placenta human chorionic gonadotrophin hcg after implantation cells within the developing placenta. The umbilical cord embryology by end of 3rd week of development embryo attached to placenta by a connecting stalk comprosed of 5 structures by the end of 1st trimester structures disappear omphaloenteric duct meckels diverticulum umbilical vesicle of the allantois umbilical ligament vitelline circulation system in the extraembryonic region. Twisted cable that connects the fetus to the placenta and carries the two umbilical arteries and a single umbilical vein vessels branch out over the fetal surface to form the villous tree average size. By the fourth month, the placenta has two components. Aug 09, 2018 pathology of the human placenta remains the most comprehensive and authoritative text in the field. The tips of the villi may coalesce, but anastomosis. In this diagram, the placenta is roughly four months old and various fundamental structures can be recognized, namely the umbilical cord, the amnion, the chorionic plate, the already advanced. The placental types in eutherian mammals are classified from various standpoints based on. One side is the fetal side, while the other is the maternal side. A comparison of the histological structure of the placenta. What are the placental barriers that must be crossed to exchange materials.
It produces numerous hormones, including estrogens and progesterone, hcg, human gh variant, and human placental lactogen. Anatomy of human placental development the human placenta develops from the trophectoderm te, the outer layerof the preimplantation embryo, which forms at. Sonographic abnormalities of the placenta and umbilical cord. Apr 30, 2014 the primary function of the placenta is to act as an interface between the dam and fetus. Development of the fetal membranes and placenta human. Jacobson, md, professor of obstetrics and gynecology, loma linda university school of medicine, loma linda center for fertility, loma. Fetuses which suffer from chromosomal problems may not be able to form a proper placenta and may miscarry, most often in the first trimester. Maternal side there are two general sides to the discshaped placenta. Scientists are divided on whether this is a good idea for humans. This site is like a library, use search box in the widget to get ebook that you want. A comparison of the histological structure of the placenta in. Describe fully the gross structure of the human placenta as observed in the laboratory. Placental structure, function and drug transfer bja. From development to disease is ideal for both experienced clinicians and researchers and those new to the field.
The great variation in placental types across mammals means that animal models have been of limited use in understanding human placental development. The placenta is an apposition of foetal and parental tissue for the purposes of physiological exchange. At this stage, the preimplantation embryo termed a blastocyst is segregated into two lineages. Development and hormonal functions of the human placenta. Anyone who needs to understand the central importance of the placenta in the well being of their maternal and fetal patients should read this book. Anatomy and tissue structure susan fisher maternalfetal interface normal term placenta.
As the maternal blood in the intervillous spaces is separated from the foetal blood by chorionic derivatives, the human placenta is known as the haemochorial type. The fullterm human placenta is a circular discoidal organ with a diameter of about 22 cm, a central thickness of 2. Pathology of the human placenta download ebook pdf, epub. Click download or read online button to get pathology of the human placenta book now. Since there are books like grays anatomy out there, it has been really difficult for a new book to create its place among those. The placenta is a key organ for pregnancy evolution and fetal growth. The placenta consists of two equal lobes connected by placental tissue. A threepart animation depicting the development and function of the human placenta. Ramsey the mature human placenta is a discoid organ 20 25 cm in diameter, 3 cm thick and weighing 400 600g internally it consists of a fetal villous tree bathed directly by maternal blood, at least during the second and third trimesters. After a complete period of gestation the child birth takes. In order to understand the chronological development of the chorionic villi it is important to have a comprehensive overview of placental anatomy. Development and physiology of the placenta and membranes glowm. The primary function of the placenta is to act as an interface between the dam and fetus.
All of the venous tributaries course toward the umbilical cord attachment site, where they empty into one. The placenta is a temporary organ that connects the developing fetus via the umbilical cord to the uterine wall to allow nutrient uptake, thermoregulation, waste elimination, and gas exchange via the mothers blood supply. Crucial placental hormones human chorionic gonadotropin hcg maintaining the corpus luteum of pregnancy stimulating secretion of testosterone by the developing testes in xy embryos. Pdf structurefunction relations in the human placenta. Since there are books like grays anatomy out there, it has been really difficult for.
The major features of the fetal side a are the chorionic plate and the umbilical cord. Placental mammals, such as humans, have a chorioallantoic placenta that forms from the chorion and allantois. In addition to the placenta providing nutrients to the fetus it also communicates to the mother, giving signals of what the fetus needs. The anatomy of the normal placenta journal of clinical. Over the years, there have been many textbooks which have been released by several authors on the subject of human anatomy. Macroscopic anatomy of the delivered placenta the fullterm human placenta is a circular discoidal organ with a diameter of about 22 cm, a central thickness of 2. Placenta functions as an endocrine gland it secretes hormones such as oestrogen, progesterone and human chorionic gonadotropin hcg. Vascular anatomy of the human placenta sciencedirect. Hormones produced by the placenta are the messengers for the needs of the fetus. Placental development implantation transfer clinical. The human haemochorial placenta is a complex and dynamic interface between embryonic and maternal tissues. The human placenta is composed of a fetal part or chorionic plate, and a maternal part or basal plate. In the late 1950s and early 1960s, the devastating series of thalidomideinduced birth defects raised awareness of the imperfect state of the placenta as a barrier to drug transfer.
Placental anatomy human family tree anatomy and embryology. Pdf synopsis background in humans, implantation is interstitial and placentation is hemochorial. Therefore, most of our knowledge about the function of the placenta has been derived from. Placentas are a defining characteristic of placental mammals, but are also found in. Morphological features of the human placenta and its free. Pathology of the human placenta 6th edition pdf free pdf.
Development and anatomy of the human placenta request pdf. Some of these hormones play a role in the regulation of fetal growth. Unfortunately, in vivo study of the human placenta is very difficult because the methodology carries with it unacceptable risks to both mother and fetus. In humans, defective placental formation underpins common pregnancy disorders such as preeclampsia and fetal growth restriction. Human placental development the human placenta is a villous placenta. The human placenta develops from the trophectoderm te, the outer layer of the preimplantation embryo, which forms at. Development and anatomy of the human placenta the placenta. The gestation period or the baby carrying period is the time from conception to birth. Review development of the human placenta the placenta is essential for normal in utero development in mammals. In this video, scott uses an expertly drawn diagram of the anatomy of the placenta to explain its structure and function. Calbindind9k cabp9k localization and levels of expression in trophoblast cells from human term placenta. After nidation, the trophoblast differentiates in two. This chapter describes the placental development, the macroscopic aspect and the.
The allantois arises as a tubular diverticulum of the posterior part of the yolksac. Influential information is extracted from the compelling narrative by. The human placenta is a unique temporary organ which ensures mutual coexistence of the organisms of mother and fetus, determining growth and development of. From development to disease examines research into placental function and its clinical implications to provide a springboard for improving clinical practice and enhancing medical research. It provides extensive information on the normal placenta, encompassing physiology, metabolism, and endocrinology, and covers the full range of placental diseases in great detail. Please be advised that we experienced an unexpected issue that occurred on saturday and sunday january 20th and 21st that caused the site to be down for an extended period of time and affected the ability of users to access content on wiley online library. The anatomic structure of the chorioallantoic placenta in eutherian mammals varies between different animal species. Development and physiology of the placenta and membranes.
Placental anatomic abnormalities may affect the placental functions, interfering in turn with maternal and or fetal. This may result when the chorionfrondosum is two small for the nutrition of the foetus, so the peripheral villi grow in such a way splitting the deciduabasalis into a superficial layer the whitish ring and a deep layer. Many animals and some human cultures make a practice of eating the placenta after it is delivered. It typically weighs approximately 500 grams just over 1 lb.
The umbilical cord is inserted in one lobe and branches from its vessels cross the membranes to the other lobe. The placenta provides the fetus with oxygen and nutrients and takes away waste such as carbon dioxide via the umbilical cord. There is considerable variation from placenta to placenta, which strongly depends on the mode of delivery. In humans, the placenta averages 22 cm 9 inch in length and 22.
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