Essentials of physiology for veterinary students / by D. Noël Paton.

  • Diarmid Noel Paton
Date:
1908
Catalogue details

Licence: Public Domain Mark

Credit: Essentials of physiology for veterinary students / by D. Noël Paton. Source: Wellcome Collection.

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    one another, but remain united by delicate lines to form a spindle-shaped structure (fig. 3, l). The spindle passes into the centre of the nucleus, and seems to direct the changes in the reticulum. The nuclear membrane disappears, and the nucleus is thus not so sharply marked off from the cell protoplasm. The nucleoli and nodal points also disappear, and with them all the finer fibrils of the network, leaving only the stouter fibres, which are now arranged either in a skein or as loops with their closed extremity to one pole of the nucleus and their open Fig. 3.—Nucleus in Mitosis : (1) Convoluted stage ; (2) Monaster stage ; (3) Dyaster stage ; (4) Complete division. extremity to the other. The nucleus no longer seems to contain a network, but appears to be filled with a convoluted mass of coarse fibres, and hence this stage of nuclear division is called the convoluted stage. The spindle continues to grow until it occupies the whole length of the nucleus. The two centrosomes are now very distinct, and from them a series of radiating lines extends out into the protoplasm of the cell. The nuclear loops of fibres break up into short, thick pieces; and these become arranged around the equator of the spindle
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