First law of thermodynamicsThe first law of thermodynamics is a formulation of the law of conservation of energy, adapted for thermodynamic processes. A simple formulation is: "The total energy in a system remains constant, although it may be converted from one form to another." Another common phrasing is that "energy can neither be created nor destroyed". While there are many subtleties and implications that may be more precisely captured in more complex formulations, this is the essential principle of the First Law.
PrimordiumA primordium (praɪˈmɔːrdiəm; : primordia; synonym: anlage) in embryology, is an organ or tissue in its earliest recognizable stage of development. Cells of the primordium are called primordial cells. A primordium is the simplest set of cells capable of triggering growth of the would-be organ and the initial foundation from which an organ is able to grow. In flowering plants, a floral primordium gives rise to a flower.
FolliculogenesisAlthough the process is similar in many animals, this article will deal exclusively with human folliculogenesis. In biology, folliculogenesis is the maturation of the ovarian follicle, a densely packed shell of somatic cells that contains an immature oocyte. Folliculogenesis describes the progression of a number of small primordial follicles into large preovulatory follicles that occurs in part during the menstrual cycle.
LyonLyon, also spelt in English as Lyons, is the third-largest city of France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of the French Alps, southeast of Paris, north of Marseille, southwest of Geneva, northeast of Saint-Étienne. The City of Lyon had a population of 522,228 in 2020 within its small municipal territory of , but together with its suburbs and exurbs the Lyon metropolitan area had a population of 2,293,180 that same year, the second most populated in France.
Germ cellA germ cell is any cell that gives rise to the gametes of an organism that reproduces sexually. In many animals, the germ cells originate in the primitive streak and migrate via the gut of an embryo to the developing gonads. There, they undergo meiosis, followed by cellular differentiation into mature gametes, either eggs or sperm. Unlike animals, plants do not have germ cells designated in early development. Instead, germ cells can arise from somatic cells in the adult, such as the floral meristem of flowering plants.
