Ovary - Anatomy & Physiology

()Map REPRODUCTIVE SYSTEM (Map) FEMALE REPRODUCTIVE TRACT

Introduction

The ovary is the female Gonad homologous to the male Testes. It is ususally a paired organ in domestic species but in the bird only the Left Ovary is present. The structures found within the ovary are undergoing constant changes throughout the oestrus cycle from the Follicles containing Oocytes, to the formation of Corpus Haemorrhagicum, Corpus Luteum, and finally Corpus Albicans. Ovaries are ellipsoidal in shape with an irregular surface due to the projection of dominant follicles and corpora lutea. These irregularities are absent in the mare due to the cortex and medulla being reversed, but are greatest in Polytocous animals such as the sow due to many dominant follicles, and so corpora lutea, developing at once.

Structure

Histological Section of a Rabbit Ovary under Low Power- Courtesy of J.Bredl, Copyright RVC 2008

Outer Tunica Albuginea

• Connective tissue layer covering the ovarian cortex.
• Overlying this structure is a single layered Germinal epithelium.

Ovarian Cortex

• This is where follicles in various stages of development are found, as well as Corpus Haemorrhagicum, Corpus Luteum and Corpus Albicans

Ovarian Medulla

• The Medulla is made up of dense connective tissue. This is where all of the lymphatics, nerves and vasculature of the Ovary are found.

Function

It has two main functions:

• Producing the female gametes oocytes via Gametogenesis.
• Producing the reproductive hormones Oestrogens and Progesterone, an endocrine function.

Processes Taking Place In The Ovary

Oogenesis

Folliculogenesis

Ovulation

Corpus Luteum Formation

Corpus Luteum Regression

Anatomical Location

• In most domestic species the ovaries lie just caudal to the kidneys and close to the tips of the uterine horns. In Ruminants the ovaries are found more caudally, close to the pelvic inlet.
• The ovaries are suspended in the abdominal cavity by the Mesovarium of the Broad Ligament.

Vasculature

• The Ovarian Artery - a direct branch off the Aorta
• The Ovarian Artery is closely associated with the Uterine Vein. This is important for the transfer of luteolytic PGF2α from the Uterus to the Ovary.