WORKSHOP IN HISTOLOGY, CYTOLOGY AND EMBRYOLOGY - 2016

Chapter 5. SPECIAL HISTOLOGY

Female Reproductive System

Slide 125. Ovary.

Staining: hematoxylin and eosin.

Magnification: x80.

First, examine the slide with the naked eye. You can distinguish the cortex containing large round follicles and the lighter, smaller medulla.

Under low magnification, we can see that the Ovary has a capsule (1) — a thin tunica albuginea covered by surface epithelium.

The ovarian cortex consists of stroma and parenchyma. The stroma is loose Connective Tissue. The parenchyma is made up of follicles at various stages of maturity: primordial, primary, secondary, and tertiary.

Primordial follicles (2) are the smallest in size and are located just beneath the capsule. They consist of a single large, round Cell — the primary oocyte with pale pink Cytoplasm and a Nucleus, surrounded by a simple squamous epithelium.

Primary follicles (3) lie deeper than the primordial ones; the primary oocyte is surrounded by the zona pellucida (4) and a single layer of simple cuboidal epithelium (5).

A secondary follicle (6) is an oocyte surrounded by a double-contoured membrane — the oolemma (zona pellucida) and stratified cuboidal epithelium. A cavity (antrum, 7) filled with serous fluid appears among its Cells. A connective tissue sheath, the theca (8), forms around the follicle.

The follicle continues to grow, becomes large, occupies almost the entire area of the cortex, and transforms into a mature follicle (Graafian follicle) (9). The mature follicle contains a primary oocyte of maximum size, surrounded by membranes — the zona pellucida and corona radiata (10). The oocyte rests on the cumulus oophorus (ovigerous mound, 11). Inside the follicle is the follicular antrum. The theca of the follicle has two layers: the theca interna (Collagen fibers, Blood Vessels, and theca endocrinocytes) and the theca externa (Cytology/practical/45.html">Dense connective tissue with thecal fibroblasts).

Follicles that degenerate without reaching maturity are called atretic follicles (primary, secondary, and tertiary) (12). They appear as a condensed pink mass (with a shrunken zona pellucida).

Corpora lutea (13) are also observed in the parenchyma — these are temporary Endocrine glands formed from the follicular epithelium and theca of a mature follicle after its rupture and ovulation. They consist of a group of yellow cells (granulosa lutein cells) interspersed with numerous blood capillaries.

The medulla contains loose Connective tissue with an Abundance of Blood and Lymphatic vessels.

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Slide 125. Ovary.