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| | The Ovaries |
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| [[Anatomy]] > [[Gray's Anatomy| Gray's Anatomy of the Human Body]] > XI. Splanchnology > 3d. 1. The Ovaries | | == Introduction == |
| | The [[ovaries]] are a pair of small, almond-shaped organs located in the female [[pelvic cavity]]. They are part of the [[female reproductive system]] and play a crucial role in [[reproduction]] and [[hormone production]]. |
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| [[Henry Gray]] (1821–1865). Anatomy of the Human Body. 1918. | | == Anatomy == |
| | Each ovary is approximately 3 cm long, 1.5 cm wide, and 1 cm thick. The ovaries are situated on either side of the [[uterus]], attached to the lateral pelvic wall by the [[suspensory ligament of the ovary]] and to the uterus by the [[ovarian ligament]]. |
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| == '''The Ovaries''' == | | === Structure === |
| '''(Ovaria)'''
| | The ovaries consist of two main regions: |
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| The '''ovaries''' are [[homologous]] with the [[testes]] in the male. They are two nodular bodies, situated one on either side of the [[uterus]] in relation to the lateral wall of the [[pelvis]], and attached to the back of the broad ligament of the uterus, behind and below the [[uterine tubes]] (Fig. 1161). The ovaries are of a grayish-pink color, and present either a smooth or a puckered uneven surface. They are each about 4 cm. in length, 2 cm. in width, and about 8 mm. in thickness, and weigh from 2 to 3.5 gm. | | * The [[cortex]], which contains the [[ovarian follicles]] at various stages of development. |
| | * The [[medulla]], which is composed of connective tissue, blood vessels, lymphatic vessels, and nerves. |
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| Each ovary presents a [[lateral]] and a [[medial]] surface, an upper or tubal and a lower or uterine extremity, and an [[anterior]] or mesovarion and a [[posterior]] free border. It lies in a shallow depression, named the '''ovarian fossa''' on the lateral wall of the pelvis; this fossa is bounded above by the external [[iliac vessels]], in front by the obliterated [[umbilical]] artery, and behind by the [[ureter]]. The exact position of the ovary has been the subject of considerable difference of opinion, and the description here given applies to the ovary of the [[nulliparous]] woman.
| | == Function == |
| | The primary functions of the ovaries include: |
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| The ovary becomes displaced during the first pregnancy, and probably never again returns to its original position. In the erect posture the long axis of the ovary is vertical. The ''tubal extremity'' is near the external [[iliac vein]]; to it are attached the ovarian [[fimbria]] of the uterine tube and a fold of [[peritoneum]], the '''suspensory ligament of the ovary''' which is directed upward over the iliac vessels and contains the ovarian vessels. | | * [[Oogenesis]]: The production of [[ova]] (egg cells) through a process called [[oogenesis]]. |
| | * [[Hormone secretion]]: The ovaries produce important hormones such as [[estrogen]] and [[progesterone]], which regulate the [[menstrual cycle]] and support [[pregnancy]]. |
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| The ''uterine end'' is directed downward toward the pelvic floor, it is usually narrower than the [[tubal]], and is attached to the lateral angle of the [[uterus]], immediately behind the [[uterine tube]], by a rounded cord termed the '''ligament of the ovary''' which lies within the broad ligament and contains some non-striped, muscular fibers. | | == Ovarian Cycle == |
| | The ovarian cycle is a series of changes that occur in the ovaries during the menstrual cycle. It consists of three phases: |
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| The ''[[lateral]] surface'' is in contact with the parietal peritoneum, which lines the ovarian [[fossa]]; the ''[[medial]] surface'' is to a large extent covered by the fimbriated extremity of the uterine tube. The ''[[mesovarian]] border'' is straight and is directed toward the obliterated umbilical artery, and is attached to the back of the broad ligament by a short fold named the '''[[mesovarium]]''' Between the two layers of this fold the bloodvessels and nerves pass to reach the [[hilum]] of the ovary. The ''free border'' is convex, and is directed toward the ureter. The uterine tube arches over the ovary, running upward in relation to its mesovarian border, then curving over its tubal pole, and finally passing downward on its free border and medial surface.
| | * [[Follicular phase]]: This phase begins on the first day of menstruation and ends with [[ovulation]]. During this phase, [[follicle-stimulating hormone]] (FSH) stimulates the growth of ovarian follicles. |
| | * [[Ovulation]]: The release of a mature egg from the dominant follicle into the [[fallopian tube]]. |
| | * [[Luteal phase]]: After ovulation, the ruptured follicle transforms into the [[corpus luteum]], which secretes progesterone to prepare the [[endometrium]] for potential implantation. |
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| | == Clinical Significance == |
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| <center>http://www.wikimd.org/images/gray/large/image1162.gif </center>
| | === Ovarian Disorders === |
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| | * [[Polycystic ovary syndrome]] (PCOS): A common endocrine disorder characterized by multiple cysts in the ovaries, irregular menstrual cycles, and elevated levels of [[androgens]]. |
| | * [[Ovarian cysts]]: Fluid-filled sacs that can form on the ovaries, often causing pain and discomfort. |
| | * [[Ovarian cancer]]: A malignant tumor that can develop in different parts of the ovary, often detected at a late stage due to subtle symptoms. |
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| FIG. 1162– Adult ovary, epoöphoron, and uterine tube. (From Farre, after Kobelt.) ''[[a, a]]'' Epoöphoron formed from the upper part of the Wolffian body. ''''b'''' Remains of the uppermost tubes sometimes forming hydatids. ''c'' Middle set of tubes. ''d'' Some lower atrophied tubes. ''e'' Atrophied remains of the Wolffian duct. ''f'' The terminal bulb or hydatid. ''h'' The uterine tube. ''[[i]]'' Hydatid attached to the extremity. ''[[l]]'' The ovary. (''Picture From the Classic Gray's Anatomy'')
| | === Diagnostic Procedures === |
| '''[[Epoöphoron (''[[parovarium; organ of Rosenmüller]]'') (Figs. 1161, 1162)]]'''—The epoöphoron lies in the mesosalpinx between the ovary and the uterine tube, and consists of a few short tubules ('''[[ductuli transversi]]''') which converge toward the ovary while their opposite ends open into a rudimentary duct, the '''[[ductus longitudinalis epoöphori]]''' (''[[duct of Gärtner]]'').
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| | * [[Ultrasound]]: A non-invasive imaging technique used to visualize the ovaries and detect abnormalities. |
| | * [[Laparoscopy]]: A surgical procedure that allows direct visualization and biopsy of the ovaries. |
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| === '''Paroophoron''' === | | == Conclusion == |
| The paroophoron consists of a few scattered [[rudimentary]] tubules, best seen in the child, situated in the broad ligament between the [[epoophoron]] and the [[uterus]]. | | The ovaries are essential organs in the female reproductive system, responsible for producing eggs and hormones. Understanding their structure and function is crucial for diagnosing and treating various ovarian disorders. |
| The ductuli transversi of the epoophoron and the tubules of the paroophoron are remnants of the tubules of the [[Wolffian body]] or mesonephros; the ductus longitudinalis epoophori is a persistent portion of the Wolffian duct.
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| In the fetus the ovaries are situated, like the [[testes]], in the [[lumbar]] region, near the kidneys, but they gradually descend into the [[pelvis]] (page 1211).
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| | {{Reproductive system}} |
| | {{Endocrine system}} |
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| <center>http://www.wikimd.org/images/gray/large/image1163.gif </center>
| | [[Category:Female reproductive system]] |
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| FIG. 1163– Section of the ovary. (After Schrön.) 1. Outer covering. 1’. Attached border. 2. Central stroma. 3. Peripheral stroma. 4. Bloodvessels. 5. Vesicular follicles in their earliest stage. 6, 7, 8. More advanced follicles. 9. An almost mature follicle. 9’. Follicle from which the ovum has escaped. 10. Corpus luteum. (''Picture From the Classic Gray's Anatomy'')
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| === '''Structure (Fig. 1163)''' ===
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| The surface of the ovary is covered by a layer of columnar cells which constitutes the '''germinal epithelium of Waldeyer''' This [[epithelium]] gives to the ovary a dull gray color as compared with the shining smoothness of the [[peritoneum]]; and the transition between the squamous epithelium of the peritoneum and the columnar cells which cover the ovary is usually marked by a line around the anterior border of the ovary. The ovary consists of a number of vesicular ovarian [[follicles]] imbedded in the meshes of a [[stroma]] or frame-work.
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| The '''[[stroma]]''' is a peculiar soft tissue, abundantly supplied with bloodvessels, consisting for the most part of spindle-shaped cells with a small amount of ordinary connective tissue. These cells have been regarded by some anatomists as unstriped muscle cells, which, indeed, they most resemble; by others as connective-tissue cells. On the surface of the organ this tissue is much condensed, and forms a layer ('''tunica albuginea''') composed of short connective-tissue fibers, with [[fusiform cells]] between them. The stroma of the ovary may contain interstitial cells resembling those of the [[testis]].
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| === '''Vesicular Ovarian Follicles (''Graafian follicles'')''' ===
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| Upon making a section of an ovary, numerous round transparent [[vesicles]] of various sizes are to be seen; they are the [[follicles]], or ovisacs containing the ova. Immediately beneath the superficial covering is a layer of stroma, in which are a large number of minute vesicles, of uniform size, about 0.25 mm. in diameter. These are the follicles in their earliest condition, and the layer where they are found has been termed the '''cortical layer''' They are especially numerous in the ovary of the young child.
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| After [[puberty]], and during the whole of the child-bearing period, large and mature, or almost mature [[follicles]] are also found in the [[cortical layer]] in small numbers, and also “corpora lutea,” the remains of follicles which have burst and are undergoing [[atrophy]] and absorption. Beneath this superficial stratum, other large and more or less mature follicles are found imbedded in the ovarian stroma. These increase in size as they recede from the surface toward a highly vascular stroma in the center of the organ, termed the '''medullary substance''' (''zona vasculosa of Waldeyer'').
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| This stroma forms the tissue of the [[hilum]] by which the ovary is attached, and through which the bloodvessels enter: it does not contain any follicles.
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| The larger follicles (Fig. 1164) consist of an external [[fibrovascular]] coat, connected with the surrounding stroma of the ovary by a net-work of bloodvessels; and an internal coat, which consists of several layers of nucleated cells, called the '''membrana granulosa''' At one part of the mature follicle the cells of the membrana granulosa are collected into a mass which projects into the cavity of the follicle. This is termed the '''discus proligerus''' and in it the ovum is imbedded. The follicle contains a transparent [[albuminous fluid]].
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| The development and maturation of the [[follicles]] and ova continue uninterruptedly from [[puberty]] to the end of the fruitful period of woman’s life, while their formation commences before birth. Before puberty the ovaries are small and the follicles contained in them are disposed in a comparatively thick layer in the [[cortical]] substance; here they present the appearance of a large number of minute closed [[vesicles]], constituting the early condition of the follicles; many, however, never attain full development, but shrink and disappear. At puberty the ovaries enlarge and become more vascular, the follicles are developed in greater abundance, and their ova are capable of [[fecundation]].
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| <center>http://www.wikimd.org/images/gray/large/image1164.gif </center>
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| FIG. 1164– Section of vesicular ovarian follicle of cat. X 50. (''Picture From the Classic Gray's Anatomy'')
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| === '''Discharge of the Ovum''' ===
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| The [[follicles]], after attaining a certain stage of development, gradually approach the surface of the ovary and burst; the ovum and fluid contents of the follicle are liberated on the exterior of the ovary, and carried into the [[uterine tube]] by currents set up by the movements of the [[cilia]] covering the mucous membrane of the [[fimbriae]].
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| === '''Corpus Luteum''' ===
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| After the discharge of the ovum the lining of the follicle is thrown into folds, and vascular processes grow inward from the surrounding tissue. In this way the space is filled up and the corpus luteum formed. It consists at first of a radial arrangement of yellow cells with bloodvessels and [[lymphatic]] spaces, and later it merges with the surrounding stroma.
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| === '''Vessels and Nerves''' ===
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| The '''[[arteries]]''' of the ovaries and uterine tubes are the [[ovarian]] from the [[aorta]]. Each [[anastomoses]] freely in the [[mesosalpinx]], with the [[uterine artery]], giving some branches to the uterine tube, and others which traverse the [[mesovarium]] and enter the [[hilum]] of the ovary.
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| The '''[[veins]]''' emerge from the hilum in the form of a [[plexus]], the '''pampiniform plexus''' the ovarian vein is formed from this plexus, and leaves the pelvis in company with the artery.
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| The '''[[nerves]]''' are derived from the [[hypogastric]] or pelvic plexus, and from the [[ovarian plexus]], the uterine tube receiving a branch from one of the uterine nerves.
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| '''Note 179''' For a description of the ovum, see page 38.
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| ==Function==
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| At [[puberty]], the ovary begins to secrete increasing levels of hormones. Secondary sex characteristics begin to develop in response to the hormones. The ovary changes structure and function beginning at puberty.<ref name=":4" /> Since the ovaries are able to regulate hormones, they also play an important role in pregnancy and fertility. When egg cells, (oocytes) are released from the Fallopian tube, a variety of feedback mechanisms stimulate the endocrine system which cause hormone levels to change.<ref>{{Cite journal|last=Richards|first=JoAnne S.|last2=Pangas|first2=Stephanie A.|date=2010-04-01|title=The ovary: basic biology and clinical implications|journal=The Journal of Clinical Investigation|volume=120|issue=4|pages=963–972|doi=10.1172/JCI41350|issn=0021-9738|pmc=2846061|pmid=20364094}}</ref> These feedback mechanisms are controlled by the hypothalamus and pituitary gland. Messages from the hypothalamus are sent to the pituitary gland. In turn, the pituitary gland releases hormones to the ovaries. From this signaling, the ovaries release their own hormones.
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| ===Gamete production ===
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| {{main|Oogenesis}}
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| The ovaries are the site of production and periodical release of [[egg cell]]s, the female gametes. In the ovaries, the developing egg cells (or [[oocyte]]s) mature in the fluid-filled [[File:Oogenesis Labeled.svg|thumb|The process of ovulation and gamete production, oogenesis, in a human ovary.]] [[ovarian follicles|follicles]]. Typically, only one oocyte develops at a time, but others can also mature simultaneously. Follicles are composed of different types and number of cells according to the stage of [[folliculogenesis|their maturation]], and their size is indicative of the stage of oocyte development.<ref name=ross>{{cite book|title=Histology: A Text and Atlas|publisher=Lippincott Williams & Wilkins|vauthors=Ross M, Pawlina W |year=2011|isbn=978-0-7817-7200-6|edition=6th}}</ref>{{rp|833}}
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| When the oocyte finishes its maturation in the ovary, a surge of [[luteinizing hormone]] secreted by the [[pituitary gland]] stimulates the release of the oocyte through the rupture of the follicle, a process called [[ovulation]].<ref name=williams>{{cite book|last1=Melmed|first1=S|last2=Polonsky|first2=KS|last3=Larsen|first3=PR|last4=Kronenberg|first4=HM|title=Williams Textbook of Endocrinology|date=2011|publisher=Saunders|isbn=978-1437703245|edition=12th|page=595}}</ref> The follicle remains functional and reorganizes into a [[corpus luteum]], which secretes [[progesterone]] in order to prepare the [[uterus]] for an eventual [[Implantation (human embryo)|implantation]] of the embryo.<ref name=ross />{{rp|839}}
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| ===Hormone secretion===
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| At maturity, ovaries secrete [[estrogen]], [[testosterone]],<ref>{{Cite news|url=http://women.webmd.com/guide/normal-testosterone-and-estrogen-levels-in-women|title=Normal Testosterone and Estrogen Levels in Women|work=WebMD|access-date=2017-11-19|language=en-US}}</ref><ref>{{Cite web|url=https://www.nlm.nih.gov/medlineplus/ency/article/003707.htm|title=Testosterone: MedlinePlus Medical Encyclopedia|website=www.nlm.nih.gov|language=en|access-date=2017-11-19}}</ref> inhibin, and [[progesterone]].<ref name=Marieb>{{cite book | last = Marieb | first = Elaine | title = Anatomy & physiology | publisher = Benjamin-Cummings | location = | page=903 | year = 2013 | isbn = 9780321887603 }}</ref>{{sfn|Venes| 2013 | p = 1702}}<ref name=":4" /> In women, fifty percent of testosterone is produced by the ovaries and [[adrenal glands]] and released directly into the blood stream.<ref>[http://med.monash.edu.au/sphpm/womenshealth/docs/androgens-in-women.pdf Androgens in women]</ref> Estrogen is responsible for the appearance of [[secondary sex characteristics]] for females at [[puberty]] and for the maturation and maintenance of the reproductive organs in their mature functional state. Progesterone prepares the uterus for pregnancy, and the mammary glands for lactation. Progesterone functions with estrogen by promoting [[menstrual cycle]] changes in the [[endometrium]].{{Medical citation needed|date=November 2017}}
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| ==Additional images==
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| <gallery>
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| File:Slide1DDD.JPG|Left Ovary
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| File:Ovaries.jpg|Ovaries
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| </gallery>
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| ==External links==
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| {{wiktionary}}
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| {{Commons category|Ovary}}
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| * [http://www.ama-assn.org//ama/pub/physician-resources/patient-education-materials/atlas-of-human-body/female-reproductive-system.page From the American Medical Association]
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| * [http://www.merckmanuals.com/home/womens_health_issues/biology_of_the_female_reproductive_system/overview_of_the_female_reproductive_system.html?qt=&sc=&alt= Merck Online Medical Library: Female Reproductive System]
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| {{Female reproductive system|state=collapsed}}
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| {{Endocrine system anatomy|state=collapsed}}
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| {{Germ cell tumors|state=collapsed}}
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| {{Female genital neoplasia|state=collapsed}}
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| {{Authority control}}
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| [[Category:Organs (anatomy)]]
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| [[Category:Endocrine system]] | | [[Category:Endocrine system]] |
| [[Category:Pelvis]] | | [[Category:Gynecology]] |
| [[Category:Human female reproductive system]]
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| [[Category:Women's health]]
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| [[Category:Gynaecology]]
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| {{grays}}
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