Q.Draw a labelled diagram of a Graafian follicle.

A Graafian follicle represents the mature stage of an ovarian follicle, ready for ovulation. While a diagram is the primary answer to this question, understanding its key components is crucial for accurate labelling.

A labelled diagram of a Graafian follicle would typically show:

• At its core, the secondary oocyte, which is the large central cell.
• Surrounding the oocyte, a non-cellular layer called the zona pellucida.
• A cluster of granulosa cells, known as the cumulus oophorus, which supports the oocyte and connects it to the follicle wall.
• A prominent, fluid-filled cavity called the antrum, which is a defining feature of a mature follicle.
• Several layers of granulosa cells lining the antrum. …

The female reproductive system, centered around the pair of ovaries, is responsible for producing female gametes (ova) and several steroid hormones. Within the ovaries, the development of ova occurs inside specialized structures called ovarian follicles. These follicles undergo a series of developmental stages, starting from primordial follicles and progressing through primary, secondary, and tertiary stages, culminating in the formation of the mature Graafian follicle.

The journey begins with primary follicles, which consist of a primary oocyte surrounded by a single layer of granulosa cells. As these follicles grow, more layers of granulosa cells are added, and a new layer called the theca layer forms around them, leading to the secondary follicle stage.

A significant transformation occurs when the secondary follicle develops a fluid-filled cavity called the antrum. This stage is known as the tertiary follicle. The formation of the antrum is a key distinguishing feature. At this point, the primary oocyte within the tertiary follicle completes its first meiotic division, resulting in a large secondary oocyte and a tiny first polar body. The secondary oocyte retains most of the cytoplasm.

The structure of a Graafian follicle is complex and highly organized, designed to protect and nourish the developing oocyte and prepare it for release. Its key components are:

• Secondary Oocyte: This is the large, centrally located female gamete, arrested in metaphase II of meiosis. It is the cell that will be ovulated.
• Zona Pellucida: A thick, non-cellular, glycoprotein layer immediately surrounding the plasma membrane of the secondary oocyte. It plays a crucial role in sperm binding and preventing polyspermy.
• Cumulus Oophorus: A mound of granulosa cells that directly surrounds the secondary oocyte and projects into the antrum. The innermost layer of these cells, directly adjacent to the zona pellucida, is often referred to as the corona radiata. …