All about Oogenesis, the Formation Process of Female Egg Cells

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Medical Video: Oogenesis How the Female Reproductive System Produces Eggs YouTube

Before the egg is mature and ready to be fertilized, a long process must be taken. This process is called oogenesis. That said, oogenesis is the initial stage of a series of reproductive processes in women. In general, oogenesis is almost similar to spermatogenesis. See the full description of oogenis until the process of ovulation below.

What is oogenesis?

Oogenesis is the process of forming an egg (ovum) in a woman, which occurs in the ovary (ovary). The ovary in the embryo has about 600 thousand oogonium cells or egg stem cells. Nine weeks after the fertilization process occurs, it turns out fetus also has begun to produce eggs. When the fetus of a baby girl is 5 months old, oogonium multiplies by mitosis until the number reaches more than 7 million primary oocytes. Unfortunately, this large number of primary oocytes will continue to decrease until the fetus is born.

From the initial number of more than 7 million primary oocytes, since the birth of primary oocytes there were only about 1 to 2 million left. These egg cells will also stop developing temporarily until you enter puberty. Now, after puberty, oogonium will actively work again following your menstrual cycle.

Of the 2 million primary oocytes, only about 400 hundred can survive until they become mature follicles. The mature follicles are small pockets that have cell walls and inside there is one egg cell. These eggs are then released during the reproductive period. It should be understood that as you get older, the quality and quantity of the remaining ovum will decrease. This is normal.

Stages of oogenesis in the ovary

Oogenesis begins with mitosis and meiosis. Mitosis is the process of cell division that produces two identical gametes (daughter cells). Meanwhile, meiosis is a cell division that produces four gametes, each of which has a number of chromosomes half of its stem cell.

Oogonium or egg stem cells will mature and mimic into primary oocytes. The primary oocyte itself will later become two parts to produce a secondary oocyte. In contrast to the process of spermatogenesis, the first meiotic division in the oogenesis process undergoes an unbalanced development of the cytoplasm (cell part).

As a result, there is one oocyte that has many cytoplasm, while the other oocytes do not have cytoplasm. Oocytes that have many cytoplasm are larger than oocytes that do not have cytoplasm. Now, this smaller oocyte is called the first polar body.

After that, the larger secondary oocytes will experience a second meiotic division that produces ootid. The first polar body will also divide into two second polar bodies. This ootid will develop into an ovum when it encounters spermatozoa aka sperm cells. This process will later experience degeneration or change. If after ootid degeneration does not meet with sperm cells and fertilization does not occur, then the oogenesis cycle repeats and you will also experience menstruation.

Understand ovulation in women

myths about ovulation

When the ovum and nucleus of the nucleus are ready to merge into one, the egg will mature and prepare to be released. The egg expenditure event is called ovulation. This ovulation occurs every month. When a woman ovulates, only one egg will mature.

There are several stages of ovulation that you need to know, including:

  1. Periovulatory. This is the stage when the layer of egg cells begins to be coated with mucus and prepares to move out into the uterus. On the other hand, the uterus is already preparing to receive eggs, so the walls will thicken.
  2. Ovulation. At this stage, there is a special enzyme that the body has to form a hole to make it easier for the egg to move through the fallopian tubes, the channel that connects the ovaries to the uterus. A mature egg will enter the channel and pass it until it reaches the uterus. In this stage, fertilization usually occurs. Fertilization (the meeting of eggs and sperm cells) occurs in the fallopian tubes and can last around 24 to 48 hours.
  3. Postovulatory. If the egg is fertilized by sperm, the egg will be immediately planted in the uterine walls with help Luteinizing hormone(LH). However, if fertilization does not occur, the egg and uterine wall that has thickened will decay. The wall of the uterus itself is filled with blood vessels, so that if the wall decays blood will emerge from the vagina. Now, this is when you experience menstruation, aka menstruation.

Various hormones that affect ovulation

In the process of ovulation, the reproductive hormone known as the GnRH hormone is released from the hypothalamus of the brain. This hormone is responsible for stimulating the release of two other main reproductive hormones such as Follicle Stimulating Hormone (FSH) and hormones luteinizing (LH) from the pituitary gland in the brain. FSH functions to stimulate the maturation of follicles in the ovary. Meanwhile LH is responsible for producing the hormones estrogen and progesterone, both of which trigger ovulation. Estrogen and progesterone hormones too causing the uterine wall to become thick to create a place for the development of fertilized eggs.

The egg will choose which sperm can reach it

Egg cells are often described as 'passive players' who only wait for the first sperm to come and enter it. In fact, research shows that eggs have a much larger role than these estimates because eggs are quite picky.

Yes, the egg will actually choose which sperm can enter it. The study also shows that eggs will trap sperm they have chosen on their surface. As a result, sperm have no other choice. When the selected sperm enters into it, the outer layer of the egg cell will harden to prevent other sperm from entering it. Now, at this time one sperm cell will meet the egg cell, known as the process of fertilization.

All about Oogenesis, the Formation Process of Female Egg Cells
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