Cytokinesis: Cytoplasmic Division
Cytokinesis: Cytoplasmic
Division
During the final stages of nuclear division a cleavage furrow appears on the surface of the dividing cell and encircles it at the midline of the spindle. The cleavage furrow deepens and pinches the plasma membrane as though it were being tightened by an invisible rubber band. Microfilaments of actin are present just beneath the surface in the furrow between the cells. Interaction with myosin, similar to that which occurs when muscle cells contract, draws the furrow inward. Finally, the infolding edges of the plasma membrane meet and fuse, completing cell division. As with other aspects of the cytoskeleton, such as the spindle, the centrosomes are responsible for locating and contracting microfilaments equidistant between them and at right angles to the spindle.
During the final stages of nuclear division a cleavage furrow appears on the surface of the dividing cell and encircles it at the midline of the spindle. The cleavage furrow deepens and pinches the plasma membrane as though it were being tightened by an invisible rubber band. Microfilaments of actin are present just beneath the surface in the furrow between the cells. Interaction with myosin, similar to that which occurs when muscle cells contract, draws the furrow inward. Finally, the infolding edges of the plasma membrane meet and fuse, completing cell division. As with other aspects of the cytoskeleton, such as the spindle, the centrosomes are responsible for locating and contracting microfilaments equidistant between them and at right angles to the spindle.
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| Figure 3-24 Stages of mitosis in whitefish. |
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