Embryo Project Encyclopedia

Endoderm is one of the germ layers-- aggregates of cells that organize early during embryonic life and from which all organs and tissues develop. All animals, with the exception of sponges, form either two or three germ layers through a process known as gastrulation. During gastrulation, a ball of cells transforms into a two-layered embryo made of an inner layer of endoderm and an outer layer of ectoderm. In more complex organisms, like vertebrates, these two primary germ layers interact to give rise to a third germ layer, called mesoderm. Regardless of the presence of two or three layers, endoderm is always the inner-most layer. Endoderm forms the epithelium-- a type of tissue in which the cells are tightly linked together to form sheets-- that lines the primitive gut. From this epithelial lining of the primitive gut, organs like the digestive tract, liver, pancreas, and lungs develop.

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.

NovaSure is a device for endometrial ablation, which is a procedure that removes the endometrium, that the US Food and Drug Administration, or FDA, approved for use on 28 September 2001. Endometrium is the tissue that lines the uterus. NovaSure destroys the endometrium by sending electric beams at the endometrium. Hologic, a medical technology company concerned with women’s health, developed NovaSure to treat menorrhagia, or heavy bleeding during menstruation. Menorrhagia is a common symptom of endometriosis. Endometriosis is the growth of the endometrium outside of the uterus. While NovaSure is not a treatment that doctors use to directly treat endometriosis, the procedure may help alleviate heavy bleeding during menstruation, which may improve a patient’s quality of life as heavy menstrual bleeding is often associated with high levels of anxiety and low levels of confidence.

The Martius flap procedure is a surgical procedure used to treat obstetric fistulas in women. Heinrich Martius developed the procedure in twentieth century Germany to treat women with urinary incontinence caused by stress, and later doctors used it to repair obstetric fistulas. Fistulas occur in pregnant women when a hole is torn between the vagina and the urinary tract (called vesicovaginal) or the vagina and the rectum (called rectovaginal). The hole, or fistula, occurs in the tissue separating two organs and therefore obstetric fistulas result in either urinary or fecal incontinence. Fistulas can occur due to surgery, injury, or chemotherapy, but they most commonly occur in pregnant women who experience prolonged labor and do not have adequate access to obstetric care. As a result of the Martius flap procedure, patients regain functional use of their vaginas without continued urinary or fecal incontinence.

Starting in 1929, the Royal College of Obstetricians and Gynaecologists was a professional association of physicians in the UK that aimed to improve the care of women in childbirth through training and education and to establish obstetrics and gynecology as a medical specialty. The Royal College of Obstetricians and Gynaecologists has contributed to women’s reproductive health by fostering research, establishing standards for physicians specializing in obstetrics and gynecology, and influencing legislation.

Felix Anton Dohrn is best remembered as the founder of the Stazione Zoologica di Napoli, the world' s first permanent laboratory devoted to the study of marine organisms. Dohrn was born on 29 December 1840 in Stettin, Pomerania (now Poland), to a wealthy merchant family. Dohrn's paternal grandfather, Heinrich, trained as a surgeon and then established a sugar refinery, while Dohrn's father, Carl August Dohrn, who inherited the family business, became interested in natural history through Alexander von Humboldt, a family friend. Once settled in his career, Anton Dohrn's own research never strayed far from the origin of vertebrates. He promoted the theory that vertebrates closely resemble and are derived from annelid-like ancestors and he spent years studying the early embryogenesis of lower vertebrates in attempts to prove this.

A germ layer is a group of cells in an embryo that interact with each other as the embryo develops and contribute to the formation of all organs and tissues. All animals, except perhaps sponges, form two or three germ layers. The germ layers develop early in embryonic life, through the process of gastrulation. During gastrulation, a hollow cluster of cells called a blastula reorganizes into two primary germ layers: an inner layer, called endoderm, and an outer layer, called ectoderm. Diploblastic organisms have only the two primary germ layers; these organisms characteristically have multiple symmetrical body axes (radial symmetry), as is true of jellyfish, sea anemones, and the rest of the phylum Cnidaria. All other animals are triploblastic, as endoderm and ectoderm interact to produce a third germ layer, called mesoderm. Together, the three germ layers will give rise to every organ in the body, from skin and hair to the digestive tract.

In Gonzales v. Carhart (2007), the US Supreme Court held in a five-to-four decision that the 2003 Partial-Birth Abortion Ban Act passed by the US Congress was constitutional. Although the Court previously ruled in Stenberg v. Carhart (2000) that a Nebraska law that prohibited partial-birth abortions was unconstitutional, Gonzales reversed this decision. Gonzales created the precedent that anyone who delivers and kills a living fetus could be subject to legal consequences, unless he or she performed the procedure to save the life of the mother.

Our Bodies, Ourselves, a succession to a pamphlet of resources pulled from co-ops of women in and around Boston, Massachusetts was published in New York in 1973 by Simon and Schuster. Retitled from the original Women and Their Bodies, Our Bodies, Ourselves was an effort by a group of educated, middle class women to reinforce women's ownership of their bodies. There have been eight editions of Our Bodies, Ourselves, as well as sequels such as Our Bodies, Ourselves: Pregnancy and Birth and Our Bodies, Ourselves: Menopause. Our Bodies, Ourselves has sold more than four million copies and been printed in twenty foreign-language editions.

Etienne Geoffroy Saint-Hilaire, commonly known as Geoffroy, studied animals, their anatomy and their embryos, and teratogens at the National Museum of Natural History in Paris, France in the eighteenth and nineteenth centuries. Geoffroy also helped develop several specialized fields in the life sciences, including experimental embryology. In his efforts to experimentally demonstrate the theory of recapitulation, Geoffroy developed techniques to intervene in the growth of embryos to see whether they would develop into different kinds of organisms. Moreover, Geoffroy emphasized the concept of l'unite de composition (the unity of plan). Geoffroy disputed in 1830 with Georges Cuvier over whether form or function matters most for the study of anatomy and whether the transformation of organic forms can occur over time. Geoffroy's conceptual contributions, as well as his experimental research, influenced embryological research on animal morphology and teratogens, and later the field of evolutionary paleontology.