How does oogenesis compared to spermatogenesis

Unlike spermatogenesis that occurs every day, oogenesis occurs once in a month, starting from puberty and ending at menopause. Similar to spermatogonia, the first female reproductive cell is the oogonia, which is a stem cell. Therefore oogonia have the ability of self-renewal and self-differentiation. Thousands of oogonia divide into around seven million germ cells from the second to the seventh month of embryonic development.

The oogonia divide by mitosis to produce the primary oocyte. These primary oocytes undergo meiotic division till the diplotene stage in the embryonic stage, after which it stalls the process of cell division and attains a quiescent stage. The cell division process is arrested until the girl attains puberty. Some primary oocytes have also been found. Most primary oocytes are destroyed, and around primary oocytes divide into gametes. Upon attaining puberty, the arrestation on the cell division process is lifted, the process continues, and primary oocytes divide into secondary oocytes.

However, this division is unequal, and one secondary oocyte and one polar body are formed from a primary oocyte. The cytoplasm is contained in the secondary oocytes, while the nucleus in the polar body is destroyed.

During ovulation, these secondary oocytes are released from the ovary. Spermatogenesis and oogenesis, although taking place in two different individuals, has certain similarities and dissimilarities. The difference between spermatogenesis and oogenesis are as follows. Production of sperm from spermatogonia. Production of an ovum from oogonia. Testis in males. Ovaries in females.

All stages of spermatogenesis take place in the testis. The last stage of oogenesis takes in the oviduct. Sperms are released from the testis. Ovums are released from the ovary. Rate of production.

Millions of sperms are produced every day. One ovum is released once per month. Spermatogenesis takes place every day from puberty until the end. Oogenesis takes place once per month from puberty to menopause. Role of Sertoli cells. Plays a supporting role during the process.

Plays no role in oogenesis. Growth phase. The Growth phase is too short. The Growth phase is prolonged. No resting stage. Resting stage takes place from the embryonic stage to puberty.

Type of cell division. Equal, resulting in the formation of four haploid spermatids. Unequal, results in the formation of one haploid ovum and two polar bodies. Size of the resulting cells. Spermatids are smaller than the spermatocyte. Ovum is larger than the oocytes. Nuclear condensation. Nuclear condensation takes place in the sperms. No nuclear condensation takes place in the ovum.

Food reservation. Very little food reservation takes place in the sperms. A lot of food and metabolite are stored in the ovum. Motility of the resulting cells. Sperms are motile. Ovums are not motile. Apart from these spermatogenesis and oogenesis differences, there are some similarities between the two processes.

The similarities between spermatogenesis and oogenesis are:. At adolescence, anterior pituitary hormones cause the development of a number of follicles in an ovary. This results in the primary oocyte finishing the first meiotic division. The cell divides unequally, with most of the cellular material and organelles going to one cell, called a secondary oocyte, and only one set of chromosomes and a small amount of cytoplasm going to the other cell.

This second cell is called a polar body and usually dies. A secondary meiotic arrest occurs, this time at the metaphase II stage. At ovulation, this secondary oocyte will be released and travel toward the uterus through the oviduct. If the secondary oocyte is fertilized, the cell continues through the meiosis II, completing meiosis, producing a second polar body and a fertilized egg containing all 46 chromosomes of a human being, half of them coming from the sperm.

Spermatogenesis occurs in the wall of the seminiferous tubules, with stem cells at the periphery of the tube and the spermatozoa at the lumen of the tube. Immediately under the capsule of the tubule are diploid, undifferentiated cells. These stem cells, called spermatogonia singular: spermatagonium , go through mitosis with one offspring going on to differentiate into a sperm cell, while the other gives rise to the next generation of sperm.

Meiosis begins with a cell called a primary spermatocyte. At the end of the first meiotic division, a haploid cell is produced called a secondary spermatocyte.

This haploid cell must go through another meiotic cell division. The cell produced at the end of meiosis is called a spermatid. Four sperm result from each primary spermatocyte that goes through meiosis. Stem cells are deposited during gestation and are present at birth through the beginning of adolescence, but in an inactive state. During adolescence, gonadotropic hormones from the anterior pituitary cause the activation of these cells and the production of viable sperm.

This continues into old age. Learning Objectives Distinguish between spermatogenesis and oogenesis. Key Points Gametogenesis, the production of sperm spermatogenesis and eggs oogenesis , takes place through the process of meiosis. In oogenesis, diploid oogonium go through mitosis until one develops into a primary oocyte, which will begin the first meiotic division, but then arrest; it will finish this division as it develops in the follicle, giving rise to a haploid secondary oocyte and a smaller polar body.

The secondary oocyte begins the second meiotic division and then arrests again; it will not finish this division unless it is fertilized by a sperm; if this occurs, a mature ovum and another polar body is produced.