Ovary

• The ovary consists of an outer cortex that surrounds the vascular medulla.
• Inside the cortex occur the ovarian follicles of various sizes.
• A layer (germinal epithelium) of cuboidal or flattened cells covers the cortex.
• The tunica albuginea, formed by dense connective tissue is found underneath the epithelium.
• There is a stroma of loose connective tissue underneath the tunica albuginea.

Follicles

• The developing follicles occur throughout the cortical stroma.
• The large follicles are suspended from the ovarian surface through cables of cortical tissue.
• Each follicle consists of a growing oocyte(ovule) that carries the vitellus(yolk) with a round nucleus(germinal vesicle).
• The oocyte is surrounded by many layers.
• These layers are, from the outside in, the theca externa, theca interna, membrana granulosa(stratum granulosum) and the perivitelline membrane.
• The Perivitelline Membrane touches the surface membrane of the oocyte.
• The theca externa is formed by a compact connective tissue that contains groups of pale luteal interstitial cells.
• The Luteal Cells can also be found in groups in the cortical stroma and in the medulla.
• The theca interna has only one fourth of the theca externa’s thickness. It is formed by a compact layer of spindle-shaped cells.
• In the larger and smaller follicles, the membrana granulosa consists of a single layer of cuboidal cells.

Oviduct

The oviduct of chickens is retorted and muscular.
• It consists, in an antero-posterior sequence, of the following five regions: infundibulum, magnum, isthmus, shell gland(uterus) and vagina.
• From the outside in, the wall of the oviduct consists of a serosa, muscularis (outer longitudinal and inner circular smooth muscles), lamina propria and epithelium.
• In most of the regions, the lamina propria contains glands.

Infundibulum

• The infundibulum is composed of a thin funneled wall and a cervical region.
• Disperse bundles of smooth muscle are situated inside the connective tissue, between the serosa and the ciliated simple columnar epithelium.
• There are longitudinal folds in the mucosa inside the funnel, close to the cervix.

Magnum

• The magnum is the longest part of the oviduct.
• Its well developed tubular glands produce albumin.
• Its mucous folds are less numerous and taller than that of the infundibulum.
• There are tertiary folds.
• The muscular layer is more developed than in the infundibulum.
• The pseudostratified epithelium is composed of columnar ciliated cells and secreting cells (goblet cells).

Isthmus

• The isthmus is a relatively short region with a smaller diameter than the magnum.
• Its longitudinal mucosa folds have numerous secondary folds.
• The muscular layer is more developed than the magnum.
• The epithelium is ciliated, pseudostratified and columnar with secreting cells.
• Its numerous tubular glands secrete the shell membranes.

Uterus

• The uterus is a portion of the expanded oviduct.
• Its walls are not as thick as those of the preceding segments.
• The muscular layer is well developed, especially the longitudinal layer.
• The mucosa is plated into longitudinal folds in the shape of leaves, covered by ciliated pseudostratified columnar epithelium.
• The shell of the egg is produced from secretions of its tubular glands.

Vagina

• The vagina is a short and narrow duct.
• Its muscular layer is well developed, especially the circular layer.
• Its mucosa is plated into numerous narrow and tall folds that have many small secondary folds.
• The surface is covered by a pseudostratified columnar epithelium with mucous cells.
• The storage of sperm occurs in the sperm-host glands.
• These tubular glands occur in the connective tissue of the vaginal mucosa, close to the junction between the uterus and vagina.
• After insemination, the sperm appears in compact masses inside the glands.
• The oviductal vagina opens into the urodeum of the cloaca.