✍️Multiplication phase During embryonic development, diploid oogonia (germinal epithelial cells of ovary) undergo repeated
mitotic divisions to increase in number
✍️Growth phase Some oogonia undergo mitosis to form primary oocytes, which remain at prophase I of meiosis, while
the rest (now called follicle cells/granulosa cells) enclose the primary oocytes.
✍️Maturation phase At p*berty, granulosa cells multiply to form primary follicle & other cell layers around the primary oocyte.
-The primary oocyte undergoes meiosis up to metaphase II only to form a secondary oocyte and 1st
polar body
The primary follicle develops to form fluid filled secondary follicle and later Graafian follicle, which
enclose secondary oocyte & 1
st polar body.
-At fertilization, the secondary oocyte completes meiosis II to form a large ootid (ovum) and second
polar body.
-The first polar body also undergoes meiosis at the same time to form two small polar bodies.
-All the three polar bodies degenerate and only one
functional egg remains