Explain the phase of maturation in oogenesis.

Explanation

(i) In maturation phase of oogenesis, primary oocyte within the tertiary follicle grows in size,
(ii) It completes its first meiotic division and forms two unequal cells (secondary oocyte and first polar body).
(iii) The secondary oocyte completes its second meiotic division , which is triggered by the sperm penetration , to form ootid and a second polar body .
(iv) The first polar body may divide to form two second polar bodies . The primary oocyte thus forms one ovum and three polar bodies .