The Binary Cellular Biology of Human Growth I Quantifying the Creation and Growth of the Body and its Parts
Assessing and understanding the Growth and Development of animals generally, and of human fetuses specifically, provides essential information for the management of the health of the newborn and its mother. Here we show that a consideration of the formation of the body, in units of numbers of cells, N, and the change in these numbers by the binary either/or decisions of cells to divide or not, an approach we call Binary Cellular Analysis, provides new insights and new equations for quantifying the growth and development of the body and its parts. These equations include: 1) The Binary Cellular Universal Growth Equation, which captures growth from conception to adulthood, and provides a method for biologically-based, data-driven, Growth Curves; 2) The Binary Cellular Universal Mitotic Fraction Equation, which lies within the Binary Cellular Universal Growth Equation, and captures the mechanism of growth to adult size, control of cell division; 3) The Binary Cellular Allometric Growth Equation, which captures the creation and growth of the Tissues, Organs, and Anatomical Structures of the body, and how the embryo creates each Body Part from a Single Founder Cell; and, 4) Binary Cellular Estimated Fetal Weight Equations, derived from the Binary Cellular Allometric Growth Equation, which captures the relationship between Ultrasound Measurement and the Size of the body as a whole. These equations capture the developmental process of Cellular Selection, resulting from Differential Cellular Proliferation, which molds the formation of the body from a single fertilized ovum into a multicellular animal. The parameters of these equations both capture the differences in Size and Growth between animals across the taxonomic spectrum, and between human fetuses, as well as identify the individual mechanisms of mitosis that drive Growth and Development. From the Binary Cellular Universal Growth Equation, the Growth of human fetuses can be measured, thus providing a much-needed tool for understanding the biological forces that cause a fetus to grow to Small, Average, or Large Size at birth, for providing the basis of biologically-based, data-driven, Growth Curves, and for assisting the management of the obstetric care of the fetus and its mother.