Cell Centre
The cell centre (Fig. 2–61) is observed in Protozoa, different cells of
multicellular animals and some plants. For the first time it is described by
Flemming (1875) and van Beneden (1876) as polar small bodies. It is
located in the centre of cell, near to the nucleus. It consists of two tubular
small bodies (0.2—0.8 μm in length, diameter of 0.1—0.2 μm). In 1895 Th.
Boveri (1887—1907) has called them centrosomes. During the cell
division they move to the poles and determine the axis of division spindle.
After division each cell obtains a pair of centrioles.
image
image
Figure 2–61. Cell centre (centrioles). Formation and migration of centrioles (asters) in round worms Ascaris (After Favard, 1961). A: Ch — chromosomes; ar — centriole; B: ar — centriole; mn — nuclear membrane, break down; er — endoplasmic bubbles.