The collective term for all the spindle fibers that form during meiosis
The spindle apparatus is the collective term for all the spindle fibers that form during mitosis or meiosis. These spindle fibers are responsible in moving and segregating the chromosomes during nuclear division. The spindle apparatus that forms during mitosis is referred to as mitotic spindle whereas the one that forms during meiosis is called meiotic spindle.
Meiosis is a specialized form of cell division that ultimately gives rise to non-identical haploid sex cells. There are two meiotic divisions and each is comprised of substages: prophase, metaphase, anaphase, and telophase. Depending on the meiotic division, they may be designated as I or II. Meiotic spindle first forms during prophase I. In the next stage, metaphase I, the spindle fibers attach to the kinetochores of the homologous chromosomes aligned along the metaphase plate. In anaphase I, the homologous chromosomes separate as they move apart towards the opposite poles. This movement is through the action of the spindle fibers. In telophase I, the spindle fibers disappear. The meiotic spindle reappears at prophase II. In metaphase II, the kinetochore microtubules attach to the kinetochores of the sister chromatids of each chromosome that line up along the metaphase plate. In anaphase II, the spindle fibers pull the sister chromatids apart and move them towards the opposite poles. In telophase II, the meiotic spindle disappears.
- spindle apparatus
- spindle fiber
- mitotic spindle
- microtubule-associated protein
- microtubule-organizing center