Female Repro Histology

Oogenesis

Process of producing female gametes

Mesovarium (suspensory ligament)

Attaches ovary to posterior of broad ligament

Cortex, medulla

Regions of ovary

Cortex of ovary

Egg development occurs here in most animals except equids

Also the site of the corpus luteum

Medulla of ovary

Includes the supporting functions for the ovary in most animals (blood vessels and lymphatics are found here)

In equids, egg development occurs in this region, while the cortical region contains blood vessels, etc.

Hilus of ovary

Region of ovary where blood vessels, nerves, and lymphatics pass through

Germinal epithelium (ovarian surface epithelium or OSE)

Low cuboidal epithelium found on the outside of the ovary

Originally thought to produce germ cells, which is not true

Tunica albuginea

Present in some species

Prominent in dogs

In some species, remnants of it may be seen

Layer of dense fibrous connective tissue (CT)

Primordial follicles

Single layer granulosa cells

Flattened

Often in groups

Primary follicles

Single layer granulosa cells

Cuboidal GC

Zona pellucida starts

Cortex

Located below the tunica albuginea in the ovary

Consists of follicles and a CT matrix between the follicles (ovarian

stroma)

Contains corpus luteum and corpus albicans

No clear demarcation where the cortex ends and the medulla begins

Primordial follicles

Single layer of flattened, squamous granulosa cells surrounding the

oocyte.

Can be found in nests or groupings of 10-20.

Begin to mature together, but only one reaches full maturity and

ovulates

The smallest follicles

Zona pellucida

Glycoprotein layer around oocyte

Synthesized by granulosa cells (GC) and oocyte

Primary follicles

About 3x larger than the primordial follicles; less numerous.

The oocyte increases in size compared to oocytes found in the primordial follicles.

Granulosa cells are cuboidal

Zona pellucida starts to form but is not clearly present

Secondary follicles

Larger than primary follicles.

The granulosa cells are stratified

The zona pellucida is prominent.

Thecal layer

CT stroma around the follicle

Antral (tertiary) follicle

Type of follicle

Antrum space filled with fluid is forming

Granulosa cells have not formed the pedicle holding the oocyte

Granulosa cells have formed tight junctions along the basement

membrane

Graafian follicle

Fully mature follicle and ready to be ovulated

Largest in size; due to:

1. Follicle antrum

2. Layers of granulosa and thecal cells

Prominent zona pellucida

Corpus luteum

Formed from the granulosa and thecal layers (endothelial and smooth muscle cells)

Consists of very large cells

Produces steroids, particularly progesterone; thus, these cells have an abundance of smooth endoplasmic reticulum (SER) and Golgi apparatus

Luteolysis

Degradation of corpus luteum that occurs at the end of luteal phase in the absence of pregnancy

Corpus albicans

During luteolysis, the CL degenerates and fills with connective tissue, forming a scar known as ___.