Embryo Project Encyclopedia Articles

Samuel Randall Detwiler was an embryologist who studied neural development in embryos and vertebrate retinas. He discovered evidence for the relationship between somites and spinal ganglia, that transplanted limbs can be controlled by foreign ganglia, and the plasticity of ganglia in response to limb transplantations. He also extensively studied vertebrate retinas during and after embryonic development. Detwiler's work established many principles studied in later limb transplantation experiments and was identified by Viktor Hamburger as an important bridge between his and Ross Granville Harrison's research.

James Marion Sims developed a surgical cure for ruptures of the wall separating the bladder from the vagina during labor, ruptures called vesico-vaginal fistulas, and he developed techniques and tools used to improve reproductive examinations and health care for women in the US during the nineteenth century. Sims's lateral examination position allowed doctors to better see the vaginal cavity, and his speculum, a spoon-like object used for increased view into the vagina, helped to make gynecological examinations more thorough. Sims helped ease the physical and social strains of post-birth women who suffered from vesico-vaginal fistulas, and he established the first hospital in New York City, New York, dedicated solely to treating women and improving women's health care.

An intrauterine pressure catheter (IUPC) is a device placed inside a pregnant woman’s uterus to monitor uterine contractions during labor. During labor, a woman’s uterus contracts to dilate, or open, the cervix and push the fetus into the birth canal. The catheter measures the pressure within the amniotic space during contractions and allows physicians to evaluate the strength, frequency, and duration of contractions. Those measurements enable physicians to evaluate the progression of labor and intervene when contractions are too weak to properly dilate a laboring woman’s cervix to successfully deliver a fetus. Though IUPCs are not used routinely, they are important in cases where external fetal monitoring is not sufficient to monitor a difficult labor. Intrauterine pressure catheters give physicians an extremely accurate measurement of intrauterine pressure, making it possible to determine whether intervention is needed to progress the labor.

In 2014, Big Belli, a media and social networking brand, released a documentary called 40 Weeks online. The documentary, directed by Christopher Henze, followed multiple women during their pregnancies. The film predominantly features three women, though it includes the stories of many. Throughout the film, women detail their accounts of the physical and emotional changes that occur during pregnancy. 40 Weeks provides viewers with information about different aspects of pregnancy including the importance of nutrition and hydration, knowledge about safe medications, and the possible complications that can affect a pregnant woman and her fetus.

In 2011, Sonja Vernes and Simon Fisher performed a series of experiments to determine which developmental processes are controlled by the mouse protein Foxp2. Previous research showed that altering the Foxp2 protein changed how neurons grew, so Vernes and Fisher hypothesized that Foxp2 would affect gene networks that involved in the development of neurons, or nerve cells. Their results confirmed that Foxp2 affected the development of gene networks involved in the growth of neurons, as well as networks that are involved in cell specialization and cell communication. The researchers determined that Foxp2 is important for a variety of developmental processes such as motor control, language acquisition, and cognition.

Camillo Golgi studied the central nervous system during the late nineteenth and early twentieth centuries in Italy, and he developed a staining technique to visualize brain cells. Called the black reaction, Golgi’s staining technique enabled him to see the cellular structure of brain cells, called neurons, with much greater precision. Golgi also used the black reaction to identify structures within animal cells like the internal reticular apparatus that stores, packs, and modifies proteins, later named the Golgi apparatus in his honor. Golgi, along with Santiago Ramón y Cajal, received the Nobel Peace Prize in 1906 for their independent work on the structure of the nervous system. Golgi’s discovery of the black reaction enabled other scientists to better study the structure of the nervous system and its development.

Scientists use cerebral organoids, which are artificially produced miniature organs that represent embryonic or fetal brains and have many properties similar to them, to help them study developmental disorders like microcephaly. In human embryos, cerebral tissue in the form of neuroectoderm appears within the first nine weeks of human development, and it gives rise to the brain and spinal cord. In the twenty-first century, Juergen Knoblich and Madeleine Lancaster at the Institute of Molecular Biotechnology in Vienna, Austria, grew cerebral organoids from pluripotent stem cells as a model to study developmental disorders in embryonic and fetal brains. One such disorder is microcephaly, a condition in which brain size and the number of neurons in the brain are abnormally small. Scientists use cerebral organoids, which they've grown in labs, because they provide a manipulable model for studying how neural cells migrate during development, the timing of neural development, and how genetic errors can result in developmental disorders.

Apoptosis, or programmed cell death, is a mechanism in embryonic development that occurs naturally in organisms. Apoptosis is a different process from cell necrosis, which is uncontrolled cell death usually after infection or specific trauma. As cells rapidly proliferate during development, some of them undergo apoptosis, which is necessary for many stages in development, including neural development, reduction in egg cells (oocytes) at birth, as well as the shaping of fingers and vestigial organs in humans and other animals. Sydney Brenner, H. Robert Horvitz, and John E. Sulston received the Nobel Prize in Physiology or Medicine in 2002 for their work on the genetic regulation of organ development and programmed cell death. Research on cell lineages before and after embryonic development may lead to new ways to reduce or promote cell death, which can be important in preventing diseases such as Alzheimer's or cancer.

The Golgi staining technique, also called the black reaction after the stain's color, was developed in the 1870s and 1880s in Italy to make brain cells (neurons) visible under the microscope. Camillo Golgi developed the technique while working with nervous tissue, which required Golgi to examine cell structure under the microscope. Golgi improved upon existing methods of staining, enabling scientists to view entire neurons for the first time and changing the way people discussed the development and composition of the brain's cells. Into the twenty-fist century, Golgi's staining method continued to inform research on the nervous system, particularly regarding embryonic development.

In 1916 Edwin B. Cragin in the United States published Conservatism in Obstetrics in which he discussed medical practices and techniques to preserve the vitality of pregnant women and their fetuses. Cragin argued that women who give birth via cesarean section, the surgical act of making an incision through both the abdomen and uterus to remove the fetus from a pregnant woman's womb, must rely on that method for future births. That claim was later coined the Dictum of Cragin. In Conservatism in Obstetrics, Cragin described obstetric techniques to maintain healthy births for women and fetuses. Cragin's article outlined the best practices for obstetricians in the early twentieth century, and publicized the claim that if a woman delivers a newborn via cesarean section, she should deliver any future newborn via the same method, a theory that persisted throughout the century.