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 ...
Using structural MRI, quantitative assessment of a number of developmental processes can be carried out including defining growth patterns, [9] and characterizing the sequence of myelination. [10] These data complement evidence from Diffusion Tensor Imaging (DTI) studies that have been widely used to investigate the development of white matter.
Neuronal precursor cells proliferate in the ventricular zone of the developing neocortex, where the principal neural stem cell is the radial glial cell. The first postmitotic cells must leave the stem cell niche and migrate outward to form the preplate, which is destined to become Cajal–Retzius cells and subplate neurons. These cells do so by ...
Mesoderm cells condense to form a rod which will send out signals to redirect the ectoderm cells above. This fold along the neural tube sets up the vertebrate central nervous system. The endoderm is the inner most germ layer of the embryo which gives rise to gastrointestinal and respiratory organs by forming epithelial linings and organs such ...
The Maturational Theory of child development was introduced in 1925 [1] by Dr. Arnold Gesell, an American educator, pediatrician and clinical psychologist whose studies focused on "the course, the pattern and the rate of maturational growth in normal and exceptional children"(Gesell 1928). [2]
Cells are specified for each segment in the early limb bud and this population of cells expand out as the limb bud grows. This model is consistent with the following observations. Cell division is seen throughout the limb bud. Cell death occurs within a 200 μm zone subjacent to the AER when it is removed; cell death forecloses some patterning.
These early stem cells are called neuroepithelial cells (NEC)s, but soon take on a highly elongated radial morphology and are then known as radial glial cells (RGC)s. [3] RGCs are the primary stem cells of the mammalian CNS, and reside in the embryonic ventricular zone , which lies adjacent to the central fluid-filled cavity ( ventricular ...
Cell growth refers to an increase in the total mass of a cell, including both cytoplasmic, nuclear and organelle volume. [1] Cell growth occurs when the overall rate of cellular biosynthesis (production of biomolecules or anabolism) is greater than the overall rate of cellular degradation (the destruction of biomolecules via the proteasome, lysosome or autophagy, or catabolism).