Ovaries

At very low magnification, the ovary appears as a roughly oval structure with two main regions: the cortex and the medulla. The cortex, which forms the outer portion of the ovary, contains numerous ovarian follicles at various stages of development embedded within a dense connective tissue stroma. These follicles—ranging from primordial to mature (Graafian) follicles—are visible as circular or oval profiles scattered throughout the cortex. The surface of the ovary is covered by a single layer of germinal epithelium, a simple cuboidal or squamous epithelium, beneath which lies a dense connective tissue layer called the tunica albuginea, giving the ovary a smooth outer appearance.

The medulla, found in the central region of the ovary, appears less cellular and more vascular than the cortex. It consists mostly of loose connective tissue, containing blood vessels, lymphatics, and nerves. At low magnification, the boundary between the cortex and medulla may appear somewhat indistinct, but the medulla is recognizable by its relative lack of follicles and the presence of prominent vascular structures.

Microscopic view of an ovary section stained pink. The structure shows an oval shape with distinct regions: A central medulla with dense, folded tissue and many antral follicles (clear and round near the periphery). The image exhibits variations in tissue density and staining intensity, providing contrast for anatomical details.
Figure 1: Microscopic view of a cross-sectioned ovary with follicles.
Microscopic image of ovarian tissue. The uppermost region features the pink-purple stained columnar cells of the ovarian surface epithelium. Below this, fibrous tissue with cells surrounds numerous round primordial follicles, each exhibiting a clearly defined nucleus stained darker. The field of view is densely packed, providing a detailed view of cellular structures. The sample is stained with hematoxylin and eosin (H&E) to enhance cellular details.
Figure 2: Microscopic view of ovary tissue with primordial follicles stained purple.

Figure 1: Ovary, H&E, 40X Slide 236a
Figure 2: Ovary, monkey, PAS, 40X Slide 269
All by University of Michigan Histology, licensed under CC BY-NC-SA 3.0.

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