Secondary oocyte consists of
Ans. d (23 X)Secondary oocyte consist of 23 X chromosomes.The chromosomal complement of a primary oocyte is 46 XX and that of secondary oocyte is 23 X.Sequence of maturation of ovarian primordial follicle after primary follicle stage:Primordial follicle(Single layered ovarian follicle)Spermatogonium (diploid, 2N) ||Primary Spermatocyte (diploid, 2N)Primordial follicle ||Secondary Spermatocyte (haploid, N)Secondary follicle (Antral follicle) ||Spermatid (haploid, N)(Spermatogenesis begins with Spermatogonia.Full development takes 2 months.It occurs in seminiferous tubules)Graffian follicle|Corpus luteum| Corpus albicans # While majority of oogonia divide, some enter into prophase of first meiotic division and are primary oocytes. These are surrounded by flat cells, which are called primordial follicles, and are present in cortex of the ovary.# At birth, there is no more mitotic division and all the oogonia are replaced by primary oocytes, which have finished prophase of first meiotic division and remain in resting phase between prophase and metaphase.# The first stage of maturation occurs with full maturation of ovarian follicle just prior to ovulation but the final maturation occurs only after fertilization.# The primary oocyte undergoes first meiotic division giving rise to secondary oocyte and one polar body.# Secondary oocyte has haploid number of chromosomes.# Ovulation occurs soon after formation of secondary oocyte.# The secondary oocyte completes the second meiotic division only after fertilization by the sperm in the fallopian tube.
46 XY
46 XX
23 Y
23 X
The Ovarian Cycle