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The placenta is a human organ which provides nutrients to a developing embryo or foetus.
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Placenta may also refer to:
The placenta is a human organ which provides nutrients to a developing embryo or foetus.
Placenta may also refer to:
The uterus or womb is the organ in the reproductive system of most female mammals, including humans, that accommodates the embryonic and fetal development of one or more embryos until birth. The uterus is a hormone-responsive sex organ that contains glands in its lining that secrete uterine milk for embryonic nourishment.
The placenta 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 physiology during pregnancy. The placenta connects to the fetus via the umbilical cord, and on the opposite aspect to the maternal uterus in a species-dependent manner. In humans, a thin layer of maternal decidual (endometrial) tissue comes away with the placenta when it is expelled from the uterus following birth. Placentas are a defining characteristic of placental mammals, but are also found in marsupials and some non-mammals with varying levels of development.
Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the fetus at a developmental stage when it is ready to feed and breathe.
Development of the human body is the process of growth to maturity. The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The resulting zygote develops through mitosis and cell differentiation, and the resulting embryo then implants in the uterus, where the embryo continues development through a fetal stage until birth. Further growth and development continues after birth, and includes both physical and psychological development that is influenced by genetic, hormonal, environmental and other factors. This continues throughout life: through childhood and adolescence into adulthood.
In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a function. Tissues of different types combine to form an organ which has a specific function. The intestinal wall for example is formed by epithelial tissue and smooth muscle tissue. Two or more organs working together in the execution of a specific body function form an organ system, also called a biological system or body system.
Matteo Realdo Colombo was an Italian professor of anatomy and a surgeon at the University of Padua between 1544 and 1559.
Placentophagy, also known as placentophagia, is the act of consuming part or all of the afterbirth following parturition in mammals. Parturition involves the delivery of the neonate, as well as the placenta and fetal membranes. The placenta is a critical organ that develops in the maternal uterus during pregnancy to support the fetus. It connects to the baby via the umbilical cord in order to allow nutrient transport, waste excretion and gas exchange between mother and baby. The morphological features of the placenta differ among species, but the function is universal. The behaviour is characteristic to the mother of the majority of placental mammals. Significant documentation has been provided on placentophagy in a range of animals. Anomalies generally include humans and aquatic species, as well as camels. However, the concept is becoming more popular among women in the Western World despite its controversial overtone.
An artificial womb or artificial uterus is a device that would allow for extracorporeal pregnancy by growing a fetus outside the body of an organism that would normally carry the fetus to term.
In humans, the circulatory system is different before and after birth. The fetal circulation is composed of the placenta, umbilical blood vessels encapsulated by the umbilical cord, heart and systemic blood vessels. A major difference between the fetal circulation and postnatal circulation is that the lungs are not used during the fetal stage resulting in the presence of shunts to move oxygenated blood and nutrients from the placenta to the fetal tissue. At birth, the start of breathing and the severance of the umbilical cord prompt various changes that quickly transform fetal circulation into postnatal circulation.
Placentation refers to the formation, type and structure, or arrangement of the placenta. The function of placentation is to transfer nutrients, respiratory gases, and water from maternal tissue to a growing embryo, and in some instances to remove waste from the embryo. Placentation is best known in live-bearing mammals (theria), but also occurs in some fish, reptiles, amphibians, a diversity of invertebrates, and flowering plants. In vertebrates, placentas have evolved more than 100 times independently, with the majority of these instances occurring in squamate reptiles.
Human embryonic development, or human embryogenesis, is the development and formation of the human embryo. It is characterised by the processes of cell division and cellular differentiation of the embryo that occurs during the early stages of development. In biological terms, the development of the human body entails growth from a one-celled zygote to an adult human being. Fertilization occurs when the sperm cell successfully enters and fuses with an egg cell (ovum). The genetic material of the sperm and egg then combine to form the single cell zygote and the germinal stage of development commences. Embryonic development in the human, covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus. The eight weeks has 23 stages.
Placental growth factor(PlGF) is a protein that in humans is encoded by the PGF gene.
Achaete-scute complex homolog 2 (Drosophila), also known as ASCL2, is an imprinted human gene.
Immune tolerance in pregnancy or maternal immune tolerance is the immune tolerance shown towards the fetus and placenta during pregnancy. This tolerance counters the immune response that would normally result in the rejection of something foreign in the body, as can happen in cases of spontaneous abortion. It is studied within the field of reproductive immunology.
Circumvallate placenta is a rare condition affecting about 1-2% of pregnancies, in which the amnion and chorion fetal membranes essentially "double back" on the fetal side around the edges of the placenta. After delivery, a circumvallate placenta has a thick ring of membranes on its fetal surface. Circumvallate placenta is a placental morphological abnormality associated with increased fetal morbidity and mortality due to the restricted availability of nutrients and oxygen to the developing fetus.
Nuclear factor -like factor 3, also known as NFE2L3 or 'NRF3', is a transcription factor that in humans is encoded by the Nfe2l3 gene.
The placenta is an organ which links the fetus to the mother in mammals for the transfer of oxygen and nutrients to the fetus and fetal waste products to the mother. Many species of mammals consume their placentas. Placentas are consumed in some human cultures. This may be for nutrition but often it has a cultural significance. For more information about the ritual consumption of placenta see Placenta: Society and culture. Human and animal placentas are also used as a source of extracts for ingredients in various consumer products such as pharmaceuticals, cosmetics, hair care products, health tonics, and food products other than ritual consumption by the mother or family. Human placentas are also used by search and rescue teams to train their search and rescue dogs to detect human remains.
Human placentophagy, or consumption of the placenta, is defined as "the ingestion of a human placenta postpartum, at any time, by any person, either in raw or altered form". While there are several anecdotes of different cultures practicing placentophagy in varying contexts, maternal placentophagy started in the US in the 1970s, with little to no evidence of its practice in any traditional or historic culture. Midwives and alternative-health advocates in the U.S. are the primary groups encouraging post-partum maternal placentophagy.
The anomaly scan, also sometimes called the anatomy scan, 20-week ultrasound, or level 2 ultrasound, evaluates anatomic structures of the fetus, placenta, and maternal pelvic organs. This scan is an important and common component of routine prenatal care. The function of the ultrasound is to measure the fetus so that growth abnormalities can be recognized quickly later in pregnancy, to assess for congenital malformations and multiple pregnancies, and to plan method of delivery.