Relationship between oocyte and follicle

Difference Between Oocyte and Follicle | Definition, Development, Anatomy, Similarities

relationship between oocyte and follicle

Reprod Fertil Dev. ;19(7) Relationship between follicle size and oocyte developmental competence in prepubertal and adult pigs. Bagg MA(1). Once the primary oocytes stop dividing the cells functional oocyte, the dominant follicles. PDF | The present study compared the distribution and steroid composition of 3-, 4- and mm follicles on the surface of prepubertal and adult.

The other follicles that begin to mature will regress and become atretic follicles, eventually deteriorating. The primary oocyte turns into a secondary oocyte in mature ovarian follicles. Unlike the sperm, the egg is arrested in the secondary stage of meiosis until fertilization. Upon fertilization by sperm, the secondary oocyte continues the second part of meiosis and becomes a zygote. Clinical significance[ edit ] Any ovarian follicle that is larger than about two centimeters is termed an ovarian cyst.

Ovarian function may be measured by gynecologic ultrasonography of follicular volume. Presently, ovarian follicle volumes can be measured rapidly and automatically from three-dimensionally reconstructed ultrasound images.

Ovary and Follicle Development

Cryopreservation of ovarian tissue is of interest to women who want to preserve their reproductive function beyond the natural limit, or whose reproductive potential is threatened by cancer therapy, [11] for example in hematologic malignancies or breast cancer. The secondary oocyte, having undergone the first meiotic division, is located eccentrically.

It is surrounded by the zona pellucida and a layer of several cells known as the corona radiata. When released from the Graafian follicle and into the oviduct, the ovum will consist of three structures: Corpus Luteum After release of the ovum, the remaining cells of the granulosa and theca interna form the corpus luteum.

The center contains the remains of the blood clot that formed after ovulation. Surrounding the clot are glanulosa lutein cells and on the outside theca lutein cells. These cells produce progesterone and to a lesser extent cholesterol. The granulosa lutein cells have an appearance characteristic of steroid-producing cells, with pale cytoplasm indicating the presence of lipid droplets.

Theca lutein cells are smaller and more deeply stained. Blood vessels penetrate into region of the granulosa lutein cells allowing them to take up cholesterol to be used to synthesize progesterone.

relationship between oocyte and follicle

The activity of the cells of the corpus luteum is sustained by leutenizing hormone. If the ovum is fertilized and implants in the uterine wall, human chorionic gonadotropin replaces leutenizing hormone to sustain the activity of the cells in the corpus luteum.

Corpus Albicans If fertilization does not occur, the cells of the corpus luteum remain active for roughly 14 days until the levels of LH fall and the corpus luteum involutes to form the corpus albicans. The secretory cells of the corpus luteum degenerate, are phagocytosed by macrophages and replaced by fibrous material. Atretic Follicle Each menstrual cycle, several primordial follicles are stimulated to continue development but only one follicles completes development to release an ovum.

The other follicles degenerate through a process called atresia which can occur at any stage of development.


During atresia, granulosa cells undergo apoptosis and are replaced by fibrous material. In the primordial follicle, zona pellucida is developed, surrounding the oocyte. The secondary follicle contains 2 to 10 layers of granulosa cells. In the tertiary follicle, a cavity appears inside the granulosa cell layer.

The Graafian follicle is relatively a large follicle. The cavity of the granulosa cell layer contains follicular fluid. The rupture of the Graafian follicle causes ovulation. Similarities Between Oocyte and Follicle Both oocyte and follicle are two developing structures found inside the ovary. The development of both oocyte and follicle occur in the ovary cortex. Both oocyte and follicle undergo simultaneous development.

The development of both oocyte and follicle is regulated by hormones.


Oocyte is a cell which develops the ovum through meiosis. Follicle is a small secretory cavity which surrounds the developing oocyte. The development process of the oocyte is called oogenesis. The developmental process of the follicle is called folliculogenesis. Stages of the Development Process Oocyte: Oogonia, primary oocyte, secondary oocyte, ootid, and ovum are the stages of the oocyte. Primordial follicle, primary follicle, secondary follicle, tertiary follicle, and Graafian follicle are the stages of the folliculogenesis.

relationship between oocyte and follicle

Oocyte consists of a haploid nucleus, cytoplasmvitelline membrane, a protective space, zona pellucida, and a corona radiata.