Aligning cell division this way in microgravity may be difficult if the microtubules of mitotic spindles are affected by the lack of gravity.They need to be investigated before a more complete picture of the process can be assembled.The experiment is generally performed with dissociated embryonic cells from specific tissues that are mixed and clumped together.Cells of differing types have different surface tensions and will sort so that the cells with greater surface tension are on the inside of a tissue and those with less surface tension are on the outside.An example of this is limb bud on the inside and epithelial cells on the outside of a group of cells. When mouse brain develops, cells migrate throughout the brain area to form six layers. If cell migration movements are altered in a developing animal the heart and other structures formed by the somites will not develop, causing early embryonic death. As there have been no births of mammals in space early embryonic death could be a direct result of microgravity.An overview of cell response to microgravity might reveal whether this is a plausible idea.Adhesion sites on the cell surface also incorporate microtubules and actin into their structure, a process that may influence cellcell interactions.Intermediate filaments also determine cell shape and support the other cytoskeleton structures of microtubules and microfilaments. Cells respond to their environment Megestrol acetate within a three dimensional tissue structure.The number of adhesive structures in a cell and its resulting cell polarity may change the way it will behave.For instance cells that are not polarized are more likely to Dolasetron undergo apoptosis. Microgravity has effects on both cell shape and cytoskeleton. Apoptosis may be affected when the cell cytoskeleton is disorganized.Alterations in this architecture can be brought about by changes in the way microtubules and other cytoskeletal components behave in microgravity. Changes in the position of cell structures such as mitochondria have been noted. Changes observed in mitochondria clustering and the area around the nuclear envelope are likely to be caused by changes in the cytoskeleton. Mitochondria clustering may cause an increase in the amount of glucose consumed by cells due to crowding.An increase in cell apoptosis is one significant consequence of the changes in cell structure and function that occur in microgravity. A cell must have polarity or it will undergo apoptosis. A cell must have a certain diameter and if it is stretched too flat it will undergo apoptosis and if it is too round it will undergo cell division. A variety of cells have been tested under microgravity conditions.Table lists some of them and the changes that were observed in microgravity.Most cells appear to exhibit cytoskeleton changes when first exposed to microgravity. Some cell types recover their cytoskeleton after approximately three days but often show signs of changes in the nucleus and in cell shape.The reactions of cells to changing gravitational fields are dependent upon cell type and length of exposure is a process that causes the elongation of tissues and occurs during gastrulation.In microgravity, this process could be altered because the lamellipodiae formed during convergent extension require microtubules.