Granulosa cell

Detailed overview of granulosa cells in the human body

Granulosa Cells

Granulosa cells are a type of somatic cell found within the ovarian follicles of the female reproductive system. These cells play a crucial role in the development and function of the ovary, particularly in the processes of oogenesis and folliculogenesis.

Structure and Location

Granulosa cells are located in the ovarian cortex, surrounding the developing oocyte within the follicle. They form multiple layers around the oocyte, starting as a single layer in primordial follicles and proliferating to form multiple layers in more mature follicles, such as the antral follicle.

File:Ovary anatomy.png

Diagram of the ovary showing the location of granulosa cells within the follicle.

Function

Granulosa cells have several key functions:

• Support of Oocyte Development: Granulosa cells provide physical support and nutrients to the developing oocyte. They are involved in the formation of the zona pellucida, a glycoprotein layer surrounding the oocyte.

• Hormone Production: These cells are responsible for the production of estrogens, particularly estradiol, through the aromatization of androgens. This process is crucial for the regulation of the menstrual cycle and the development of secondary sexual characteristics.

• Follicular Fluid Secretion: Granulosa cells secrete follicular fluid, which fills the antrum of the follicle and is essential for follicle expansion and oocyte maturation.

• Regulation of Follicle Maturation: Through the production of inhibin and activin, granulosa cells regulate the secretion of follicle-stimulating hormone (FSH) from the pituitary gland, thus controlling follicle maturation.

Role in the Menstrual Cycle

During the menstrual cycle, granulosa cells undergo significant changes. In the follicular phase, they proliferate and increase in number, contributing to the growth of the follicle. As the follicle matures, granulosa cells increase their production of estradiol, leading to the LH surge that triggers ovulation. After ovulation, the remaining granulosa cells transform into luteal cells and form the corpus luteum, which secretes progesterone to maintain the endometrium for potential implantation.

Clinical Significance

Granulosa cells are involved in several clinical conditions:

• Granulosa Cell Tumors: These are rare ovarian tumors that arise from granulosa cells. They can produce estrogen, leading to symptoms such as abnormal uterine bleeding.

• Polycystic Ovary Syndrome (PCOS): In PCOS, the function of granulosa cells is often disrupted, leading to anovulation and hormonal imbalances.

• Infertility: Dysfunctional granulosa cells can contribute to infertility due to impaired follicle development and hormone production.

Related Pages

• Ovarian follicle
• Oocyte
• Estrogen
• Follicle-stimulating hormone
• Luteinizing hormone
• Corpus luteum