For this semester, I need to know the whole process for ovogénèse. Yes, it's in French and a lot more terminology below in this text will be for I am learning about this in that nomenclature. So I figured instead of just writing on the computer the story of what it is, I'll blog about it so I can come back to it later on and leave it out there on the Net if someone else ever finds it to help them as well.
Once upon a time.... there was a reproductive system in the human female body. In this reproductive system, there was magic which all starts in the ovaries. Within the ovaries, ovules are formed. There are two zones within the ovaries, the zone corticale which contains the organites ovariens (follicules and what derives from them to form the ovules) and the zone médullaire, where we find the paquet vasculo-nerveux that gives nourishment to the ovary.
A 7-month old female embryo is estimated to have 7 million primordial follicules that form ovules in their ovaries. At birth, these contain only 1 million and by puberty 400,000 remain. The number just keeps going down until menopause. In the life of a woman, it is said calculate that only 300 to 400 follicules attain to a full ovulation cycle.
In the ovary, the primordial cells that will form ovules are called : ovogonies. When one gets to a mature state, it's called ovocyte 1. Ovocyte 1 blocked in Prophase 1 has a nucleus and a membrane. The ovocyte 1 becomes surrounded by des cellules folliculeuses aplaties within the stroms cortical, among the capillaires sanguins. All these flatten out cells around the ovocyte 1 multiply in number, while still surrounding the ovocyte 1. Consequently, they become cubic shaped, cellule folliculeuse cubique, these form the Slavjanski membrane. From that point the whole ovocyte 1 follicule enters in secondary phase. The cellules folliculeuses cubiques multiply in layers around the ovocyte 1 and this thickness of layers, underneith the Slajvanski membrane, are called the granulosa. While the granulosa cells around the ovocyte secrete a gel, this layer of gel around it becomes the zone Pellucide. Starting from the middle going inside-out, you have the ovocyte, the Pellucide zone, the granulosa, the Slajvanski membrane, and last there is la thèque interne. In la thèque interne, there are capillaires sanguins and cellules épithéloïdes.
The next stage is called jeune follicule cavitaire. Everything get bigger, especially because the cells of the granulosa keep secreting the gel like matter. Little type-like puddles are form within the granulosa which are called corps de Call et Exner. When a whole punch of them gather together, it forms the ANTRUM. The follicule keeps getting bigger, more epithéloïde cells attached themselves to capillaires sanguins. Around the thèque interne there is now a thèque externe. The thèque externe contains myofibroblastes, which are hybrid cells that the thèque interne doesn't have. Connexed inside the antrum, the ovocyte with the pellucide zone and some layers of the granulosa demarked themselves to become the cumulus (or oophorus). The cells from the cumulus start secreting hyaluronique acid, which accumulates in the atrium and the whole follicule gets bigger, and become préovulatoire. The hyaluronique acid makes the cumulus detach itself from the granulosa and as it's floating withing the antrum, it become a corona radiata.When the follicule préovulatoire is at its biggest, an apex is form towards the epithélium ovarien.
By Day 14 of the menstrual cycle, the ovulation period is where LH and RSH peak. This peak in LH necroses related tissues of the apex and the follicule bursts. This sudden change of pressure withing the antrum make the myofibroblastes, of the thèque externe, contract which pushes the corona radiata outside of the ovary to become an ovule.
The ovocyte 1 becomes now an ovocyte 2 when expulsed. What's left behind in the zone corticale of the ovary becomes the corps jaune. The Slajvanski membrane deteriorates from the follicule, and this latter shrivels while the thèque layers mingle with the granulosa. Starting from the middle going inside-out of the corps jaune, you have coagulum central, organisation fibreuse, grandes cellules lutéales (which were the granulosa), petites cellules lutéales (which were the thèque interne cells) and the thèque. If the egg is fertilize, the corps jaune will hang out in the ovary's zone corticale to secrete the needed hormones for the fertilized egg until it can sustain itself in the endometer part of the uterus. If the ovule didn't meet it "prince charming" sperm, or when there's embryo, the corps jaune degenerates and becomes a corpus albican, or corps blanc.
That's it! I'm not putting any pictures because I need to know this stuff by heart. When I read it, I see the images in my mind. Basically, I'm purposely making my brain work harder. Now for men this week!!!
No comments:
Post a Comment