Search results
Results from the WOW.Com Content Network
This trend continues postnatally along an axis of increased growth from the head to the feet. Finally, in adults, the head represents approximately 12% of the body length. The cephalocaudal trend is also the trend of infants learning to use their upper limbs before their lower limbs. The proximodistal trend, on the other hand, is the prenatal ...
Gesell and his colleagues documented a set of behavioral norms that illustrate sequential & predictable patterns of growth and development. Gesell asserted that all children go through the same stages of development in the same sequence, although each child may move through these stages at their own rate [ 3 ] Gesell's Maturational Theory has ...
The small intestine forms loops (B2) and slides back into the abdomen (B3) during resolution of the hernia. Meanwhile, the cecum moves from the left to the right side, which represents the additional 180° counterclockwise rotation of the intestine (C, central view). [3] In the process of lengthening growth, the intestinal duct herniates and
The Shh gene, and genes belonging to the BMP, Hox, T-box, FGF, and Wnt families, all play a pivotal role in cell signaling and differentiation to regulate and promote successful limb formation. Various other genes listed above, one example being Dach1, are DNA-binding proteins that regulate gene expression.
For example, stem cells requires the sox2 gene to maintain pluripotency and is used to detect enduring concentrations of stem cells in CNS tissue. The protein nestin is an intermediate filament , which is essential for the radial growth of axons , and is therefore used to detect the formation of new synapses .
In biological terms, human development entails growth from a one-celled zygote to an adult human being. Fertilization occurs when the sperm cell successfully enters and fuses with an egg cell . [2] The genetic material of the sperm and egg then combine to form a single cell called a zygote and the germinal stage of prenatal development commences.
Each cell type is defined by its particular pattern of regulated gene expression. Cell differentiation is thus a transition of a cell from one cell type to another and it involves a switch from one pattern of gene expression to another. Cellular differentiation during development can be understood as the result of a gene regulatory network.
[4] [5] [6] Pattern formation is genetically controlled, and often involves each cell in a field sensing and responding to its position along a morphogen gradient, followed by short distance cell-to-cell communication through cell signaling pathways to refine the initial pattern. In this context, a field of cells is the group of cells whose ...