Mesoderm is one of the three germ layers, groups of cells that interact early during the embryonic life of animals and from which organs and tissues form.
Étienne 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.
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.
Ectoderm is one of three germ layers—groups of cells that coalesce early during the embryonic life of all animals except maybe sponges, and from which organs and tissues form. As an embryo develops, a single fertilized cell progresses through multiple rounds of cell division.
Tooth enamel contains relics of its formation process, in the form of microstructures, which indicate the incremental way in which it forms during enamel formation on teeth
Frederik Ruysch, working in the Netherlands, introduced the term epithelia in the third volume of his Thesaurus Anatomicus in 1703. Ruysch created the term from the Greek epi, which means on top of, and thele, which means nipple, to describe the type of tissue he found when dissecting the lip of a cadaver.
Andreas Vesalius, also called Andries van Wesel, studied anatomy during the sixteenth century in Europe. Throughout his career, Vesalius dissected numerous human cadavers, and took detailed notes and drawings of the human anatomy. Compiling his research, Vesalius published an anatomy work titled De humani corporis fabrica libri septem ("On the fabric of the human body in seven books"). The Fabrica included
Isidore Geoffroy Saint-Hilaire studied anatomy and congenital abnormalities in humans and other animals in nineteenth century France. Under the tutelage of his father, Étienne Geoffroy Saint-Hilaire, Isidore compiled and built on his father's studies of individuals with developmental malformations, then called monstrosities.