Human body from organs to the cells of which they are composed. The human body consists of many interacting systems of organs. These interact to maintain homeostasis, keeping the body in a stable state with safe levels of substances such as sugar and oxygen in the blood. Each system contributes to homeostasis, of itself, other systems, and the entire body. Some combined systems are referred to by joint names. For example, the nervous system and the endocrine system operate together as the neuroendocrine system. The nervous system receives information from the body, and transmits this to the brain via nerve impulses and
Radial glial cell to replace lost or damaged tissue in a process known as gliosis. Radial glial cells originate from the transformation of neuroepithelial cells that form the neural plate during the early phases of pre-natal neurogenesis. This process is mediated through the down-regulation of epithelium-related protein expression (such as tight junctions) and an up-regulation of glial-specific features such as glycogen granules, the astrocyte glutamate transporter (GLAST), the intermediate filament vimentin, and, in some instances, including humans, glial fibrillary acidic protein (GFAP). After this transition, radial glia retain many of the original characteristics of neuroepithelial cells including: their apical-basal polarity, their position along