Folliculogenesis: Difference between revisions
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=== Tertiary Follicle === | === Tertiary Follicle === | ||
The tertiary follicle, or antral follicle, is marked by a large antrum and further differentiation of the theca and granulosa cells. The oocyte is now surrounded by the cumulus oophorus, a cluster of cells that support its development. | The tertiary follicle, or antral follicle, is marked by a large antrum and further differentiation of the theca and granulosa cells. The oocyte is now surrounded by the cumulus oophorus, a cluster of cells that support its development. | ||
Latest revision as of 18:48, 21 February 2025
Folliculogenesis[edit]
Folliculogenesis is the maturation process of the ovarian follicle, a spherical aggregation of cells found in the ovary. This process is crucial for the development of a mature oocyte capable of fertilization. Folliculogenesis occurs in several stages, beginning with primordial follicles and culminating in the formation of a pre-ovulatory or Graafian follicle.
Stages of Folliculogenesis[edit]
Folliculogenesis can be divided into several distinct stages:
Primordial Follicle[edit]
The primordial follicle is the earliest stage of follicle development. It consists of a primary oocyte surrounded by a single layer of flattened granulosa cells. These follicles are formed during fetal development and remain dormant until they are recruited into the growing pool.
Primary Follicle[edit]
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In the primary follicle stage, the oocyte enlarges, and the surrounding granulosa cells become cuboidal. The zona pellucida, a glycoprotein layer, begins to form around the oocyte.
Secondary Follicle[edit]
The secondary follicle is characterized by the proliferation of granulosa cells and the formation of a fluid-filled cavity called the antrum. The theca layer, consisting of theca interna and theca externa, also develops around the follicle.
Tertiary Follicle[edit]
The tertiary follicle, or antral follicle, is marked by a large antrum and further differentiation of the theca and granulosa cells. The oocyte is now surrounded by the cumulus oophorus, a cluster of cells that support its development.
Graafian Follicle[edit]
The Graafian follicle, or pre-ovulatory follicle, is the final stage of folliculogenesis. It is characterized by a large antrum and a mature oocyte ready for ovulation. The follicle bulges from the surface of the ovary, and the cumulus oophorus detaches, allowing the oocyte to be released during ovulation.
Hormonal Regulation[edit]
Folliculogenesis is tightly regulated by hormones such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH promotes the growth and maturation of follicles, while LH triggers ovulation and the formation of the corpus luteum.
Follicular Atresia[edit]
Not all follicles reach the Graafian stage; many undergo a process called atresia, where they degenerate and are reabsorbed by the ovary. Atresia is a natural part of folliculogenesis, ensuring that only the healthiest follicles reach maturity.
Histology[edit]
Histological examination of ovarian tissue reveals the various stages of follicle development, from primordial to Graafian follicles. Each stage is characterized by distinct cellular arrangements and structures.
Clinical Significance[edit]
Disruptions in folliculogenesis can lead to infertility and other reproductive disorders. Conditions such as polycystic ovary syndrome (PCOS) are associated with abnormal follicle development and hormonal imbalances.
