Difference between revisions of "Ovary - Anatomy & Physiology"
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| − | + | == Headline text == | |
| + | {{toplink | ||
| + | |backcolour =EED2EE | ||
| + | |linkpage =Reproductive System - Anatomy & Physiology | ||
| + | |linktext =Reproductive System | ||
| + | |maplink = Reproductive System (Content Map) - Anatomy & Physiology | ||
| + | |pagetype =Anatomy | ||
| + | |sublink1=Reproductive System - Anatomy & Physiology#Female Reproductive Tract | ||
| + | |subtext1=FEMALE REPRODUCTIVE TRACT | ||
| + | }} | ||
| + | <br> | ||
==Introduction== | ==Introduction== | ||
| − | The ovary is the female Gonad homologous to the male Testes. It is | + | 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 [[The Ovary_-_Follicles_-_Anatomy_%26_Physiology|Follicles]] containing [[The Ovary_-_Oocytes_-_Anatomy_%26_Physiology|Oocytes]], to the formation of [[Corpus Haemorrhagicum]],Corpus Luteum, and finally [[The Ovary_-Corpus Albicans_-_Anatomy_%26_Physiology|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 with ovulation only occuring from the ovulation fossa, but are greatest in [[Gestation_-Litter Sizes_-_Anatomy_%26_Physiology|Polytocous]] animals such as the sow due to many dominant follicles, and so corpora lutea, developing at once. |
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==Structure== | ==Structure== | ||
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=== Ovarian Cortex === | === Ovarian Cortex === | ||
| − | * | + | *This is where [[The Ovary_-_Follicles_-_Anatomy_%26_Physiology|Follicles]] in various stages of development are found, as well as [[Corpus Haemorrhagicum]], Corpus Luteum and [[Corpus Albicans]] |
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=== Ovarian Medulla === | === Ovarian Medulla === | ||
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*The Medulla is made up of dense connective tissue. This is where all of the lymphatics, nerves and vasculature of the Ovary are found. | *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== | ||
| + | |||
| + | === [[The Ovary - Oogenesis - Anatomy & Physiology|Oogenesis]] === | ||
| − | === | + | === [[The Ovary_-_Follicles_-_Anatomy_%26_Physiology|Folliculogenesis]] === |
| − | [[ | ||
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| + | === [[The Ovary - Ovulation - Anatomy & Physiology|Ovulation]] === | ||
| + | === [[The Ovary - Corpus Luteum Formation - Anatomy & Physiology|Corpus Luteum Formation]] === | ||
| + | === [[The Ovary - Corpus Luteum Regression- Anatomy & Physiology|Corpus Luteum Regression]] === | ||
| + | |||
| + | ==Anatomical Location== | ||
| + | * In the '''dog and cat''', ovaries do not migrate in development. They remain in the dorsal part of the abdomen, caudal to the kidneys at the tip of the uterine horns. | ||
| + | * In other domestic species, the ovaries migrate during development. | ||
| + | * The greatest degree of migration occurs in '''ruminants'''. Here, the ovaries come to lie close to the ventral abdominal wall, cranial to the pelvic inlet. | ||
| + | * In the '''pig''', they descend to the middle of the abdomen. | ||
| + | * In the '''mare''', they are located ~8-10 cm ventral to the dorsal wall of the abdomen. | ||
| + | *The ovaries are suspended in the abdominal cavity by the Mesovarium of the [[The Uterus_-_The Broad Ligament_-_Anatomy_%26_Physiology|Broad Ligament]]. | ||
==Histology== | ==Histology== | ||
| − | [[Image:Ovary low magnification.jpg|thumb|right| | + | [[Image:Ovary low magnification.jpg|thumb|right|150px|Histological Section of a Rabbit Ovary under Low Power- Courtesy of J.Bredl, Copyright RVC 2008]] |
=== Stroma === | === Stroma === | ||
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** ground substance | ** ground substance | ||
* Stromal cells resemble fibroblasts, but some contain lipid droplets. | * Stromal cells resemble fibroblasts, but some contain lipid droplets. | ||
| − | * | + | * Budles of smooth muscle cells are scattered throughout the stroma. |
=== Cortex === | === Cortex === | ||
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* Atretic Follicles | * Atretic Follicles | ||
* Corpora lutea | * Corpora lutea | ||
| − | * Corpora | + | * Corpora albicantes |
* The superficial cortex is more fibrotic than the deep, and is called the tunica albuginea. | * The superficial cortex is more fibrotic than the deep, and is called the tunica albuginea. | ||
* On the surface of the ovary is the germinal epithelium. This is a continuation of the peritoneum. | * On the surface of the ovary is the germinal epithelium. This is a continuation of the peritoneum. | ||
| Line 65: | Line 76: | ||
* Highly vascular | * Highly vascular | ||
| − | * Contains hilus cells, which are similar to the Leydig cells of the | + | * Contains hilus cells, which are similar to the Leydig cells of the testes. |
==Vasculature== | ==Vasculature== | ||
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=== Arterial Supply === | === Arterial Supply === | ||
| − | * The ovarian artery (a branch of the Aorta) and ovarian branches of the Uterine artery form anastomoses in the mesovarium and the | + | * The ovarian artery (a branch of the Aorta) and ovarian branches of the Uterine artery form anastomoses in the mesovarium and the broad ligament. |
* From this arterial plexus ~10 coiled Helicine arteries enter the hilus of the ovary. | * From this arterial plexus ~10 coiled Helicine arteries enter the hilus of the ovary. | ||
* Smaller branches form a plexus at the corticomedullary junction, giving rise to straight Cortical arterioles, which radiate into the cortex. | * Smaller branches form a plexus at the corticomedullary junction, giving rise to straight Cortical arterioles, which radiate into the cortex. | ||
* Here they branch and anastomose to form vascular arcades, which give rise to a rich capillary network around follicles. | * Here they branch and anastomose to form vascular arcades, which give rise to a rich capillary network around follicles. | ||
| − | + | ||
=== Venous Drainage === | === Venous Drainage === | ||
* Venous drainage follows the course of the arterial system. | * Venous drainage follows the course of the arterial system. | ||
* Medullary veins are large and tortuous. | * Medullary veins are large and tortuous. | ||
| − | * The Ovarian Artery is closely associated with the Uterine Vein. This is important for the transfer of luteolytic PGF2α from the | + | * 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. |
== Lymphatics == | == Lymphatics == | ||
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== Innervation == | == Innervation == | ||
| − | * Sympathetic fibres of the autonomic nervous system supply blood vessels and terminate on | + | * Sympathetic fibres of the autonomic nervous system supply blood vessels and terminate on smooth muscle cells in the stroma around follicles. |
* May play a role in follicular maturation and ovulation, but the main control is via the endocrine system. | * May play a role in follicular maturation and ovulation, but the main control is via the endocrine system. | ||
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Revision as of 07:57, 10 September 2008
Headline text
|
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 with ovulation only occuring from the ovulation fossa, but are greatest in Polytocous animals such as the sow due to many dominant follicles, and so corpora lutea, developing at once.
Structure
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 the dog and cat, ovaries do not migrate in development. They remain in the dorsal part of the abdomen, caudal to the kidneys at the tip of the uterine horns.
- In other domestic species, the ovaries migrate during development.
- The greatest degree of migration occurs in ruminants. Here, the ovaries come to lie close to the ventral abdominal wall, cranial to the pelvic inlet.
- In the pig, they descend to the middle of the abdomen.
- In the mare, they are located ~8-10 cm ventral to the dorsal wall of the abdomen.
- The ovaries are suspended in the abdominal cavity by the Mesovarium of the Broad Ligament.
Histology
Stroma
- The body of the ovary (ovarian stroma) consists of:
- spindle-shaped cells
- fine collagen fibres
- ground substance
- Stromal cells resemble fibroblasts, but some contain lipid droplets.
- Budles of smooth muscle cells are scattered throughout the stroma.
Cortex
- Follicles containing oocytes in various stages of development.
- Atretic Follicles
- Corpora lutea
- Corpora albicantes
- The superficial cortex is more fibrotic than the deep, and is called the tunica albuginea.
- On the surface of the ovary is the germinal epithelium. This is a continuation of the peritoneum.
Medulla
- Highly vascular
- Contains hilus cells, which are similar to the Leydig cells of the testes.
Vasculature
Arterial Supply
- The ovarian artery (a branch of the Aorta) and ovarian branches of the Uterine artery form anastomoses in the mesovarium and the broad ligament.
- From this arterial plexus ~10 coiled Helicine arteries enter the hilus of the ovary.
- Smaller branches form a plexus at the corticomedullary junction, giving rise to straight Cortical arterioles, which radiate into the cortex.
- Here they branch and anastomose to form vascular arcades, which give rise to a rich capillary network around follicles.
Venous Drainage
- Venous drainage follows the course of the arterial system.
- Medullary veins are large and tortuous.
- 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.
Lymphatics
- Arise in the perifollicular stroma.
- Drain into larger vessels, which coil around the medullary veins.
Innervation
- Sympathetic fibres of the autonomic nervous system supply blood vessels and terminate on smooth muscle cells in the stroma around follicles.
- May play a role in follicular maturation and ovulation, but the main control is via the endocrine system.