. A text-book of physiology : for medical students and physicians . a; s, perivitellin space. V &• /• the egg reaches the Fal-lopian tube its nucleus undergoes the changes preparatory toa mitotic division. The changes that occur in an ordinary celldivision are represented schematically in Fig. 303. The nucleusat first presents the ordinary. chromatin network, and in thecytoplasm lies the minute structure known as the latter divides into two daughter-centrosomes (&) which moveto opposite sides of the nucleus and become surrounded by rays,each centrosome with its radiating system
. A text-book of physiology : for medical students and physicians . a; s, perivitellin space. V &• /• the egg reaches the Fal-lopian tube its nucleus undergoes the changes preparatory toa mitotic division. The changes that occur in an ordinary celldivision are represented schematically in Fig. 303. The nucleusat first presents the ordinary. chromatin network, and in thecytoplasm lies the minute structure known as the latter divides into two daughter-centrosomes (&) which moveto opposite sides of the nucleus and become surrounded by rays,each centrosome with its radiating system forming an astro-sphere. The chromatin material in the nucleus meanwhile hascollected into larger threads known as chromosomes (c), andthe nuclear membrane disappears (d). The number of chromo-somes is definite for each species of animal. The chromosomesarrange themselves equatorially between the astrospheres and theneach divides longitudinally into two parts (/). These parts migrateor are drawn toward their respective centrosomes (g, h, i), and this.
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