Development of the endocrine system alpha cells. The insulin concentration within the fetal pancreas is 3.6 pmol/g at seven to ten weeks, which rises to 30 pmol/g at 16–25 weeks of gestation. Near term, the insulin concentration increases to 93 pmol/g. The endocrine cells have dispersed throughout the body within 10 weeks. At 31 weeks of development, the islets of Langerhans have differentiated. While the fetal pancreas has functional beta cells by 14 to 24 weeks of gestation, the amount of insulin that is released into the bloodstream is relatively low. In a study of pregnant women carrying fetuses in the mid-gestation and near term
Passions of the Soul of a final cause in physics, the nature of his work on examining the origins and functions of desires in the human soul necessitates the existence of a final goal towards which the individual is working. The problem of the "Passions" treatise is also the problem of Cartesian Dualism. In the first part of his work, Descartes ponders the relationship which exists between the thinking substance and the body. For Descartes, the only link between these two substances is the pineal gland (art. 31), the place where the soul is attached to the body. The passions that Descartes studies are