Ovary
Overview
"Ovaria" redirects here. This is also a proposed section
Section (botany)
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...

 and a synonym
Synonym
Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...

 of
Solanum
Solanum
Solanum, the nightshades, horsenettles and relatives, is a large and diverse genus of annual and perennial plants. They grow as forbs, vines, subshrubs, shrubs, and small trees, and often have attractive fruit and flowers. Many formerly independent genera like Lycopersicon or Cyphomandra are...

.

The ovary is an ovum
Ovum
An ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...

-producing reproductive organ, often found in pairs as part of the vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...

 female
Female
Female is the sex of an organism, or a part of an organism, which produces non-mobile ova .- Defining characteristics :The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male...

 reproductive system
Reproductive system
The reproductive system or genital system is a system of organs within an organism which work together for the purpose of reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. Unlike most organ systems, the sexes...

. Ovaries in anatomically female individuals are analogous to testes
Testicle
The testicle is the male gonad in animals. Like the ovaries to which they are homologous, testes are components of both the reproductive system and the endocrine system...

 in anatomically male individuals, in that they are both gonad
Gonad
The gonad is the organ that makes gametes. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells. For example, spermatozoon and egg cells are gametes...

s and endocrine glands.
Ovaries are oval shaped. The ovary (for a given side) is located in the lateral wall of the pelvis in a region called the ovarian fossa
Ovarian fossa
The ovary lies in a shallow depression, named the ovarian fossa, on the lateral wall of the pelvis.This fossa has the following boundaries:* superiorly: by the external iliac vessels* anteriorly and inferiorly: by the broad ligament of the uterus...

.
Encyclopedia
"Ovaria" redirects here. This is also a proposed section
Section (botany)
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...

 and a synonym
Synonym
Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...

 of
Solanum
Solanum
Solanum, the nightshades, horsenettles and relatives, is a large and diverse genus of annual and perennial plants. They grow as forbs, vines, subshrubs, shrubs, and small trees, and often have attractive fruit and flowers. Many formerly independent genera like Lycopersicon or Cyphomandra are...

.

The ovary is an ovum
Ovum
An ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...

-producing reproductive organ, often found in pairs as part of the vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...

 female
Female
Female is the sex of an organism, or a part of an organism, which produces non-mobile ova .- Defining characteristics :The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male...

 reproductive system
Reproductive system
The reproductive system or genital system is a system of organs within an organism which work together for the purpose of reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. Unlike most organ systems, the sexes...

. Ovaries in anatomically female individuals are analogous to testes
Testicle
The testicle is the male gonad in animals. Like the ovaries to which they are homologous, testes are components of both the reproductive system and the endocrine system...

 in anatomically male individuals, in that they are both gonad
Gonad
The gonad is the organ that makes gametes. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells. For example, spermatozoon and egg cells are gametes...

s and endocrine glands.

Human anatomy

Ovaries are oval shaped. The ovary (for a given side) is located in the lateral wall of the pelvis in a region called the ovarian fossa
Ovarian fossa
The ovary lies in a shallow depression, named the ovarian fossa, on the lateral wall of the pelvis.This fossa has the following boundaries:* superiorly: by the external iliac vessels* anteriorly and inferiorly: by the broad ligament of the uterus...

. The fossa usually lies beneath the external iliac artery
External iliac artery
The external iliac arteries are two major arteries which bifurcate off the common iliac arteries anterior to the sacroiliac joint of the pelvis. They proceed anterior and inferior along the medial border of the psoas major muscles...

 and in front of the ureter
Ureter
In human anatomy, the ureters are muscular tubes that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually long and ~3-4 mm in diameter....

 and the internal iliac artery
Internal iliac artery
The internal iliac artery is the main artery of the pelvis.-Structure:The internal iliac artery supplies the walls and viscera of the pelvis, the buttock, the reproductive organs, and the medial compartment of the thigh...

.

The ovaries aren't attached to the fallopian tube
Fallopian tube
The Fallopian tubes, also known as oviducts, uterine tubes, and salpinges are two very fine tubes lined with ciliated epithelia, leading from the ovaries of female mammals into the uterus, via the utero-tubal junction...

s but to the outer layer of the uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...

 via the ovarian ligaments. Usually each ovary takes turns releasing eggs every month; however, if there was a case where one ovary was absent or dysfunctional then the other ovary would continue providing eggs to be released.

Hormones

Ovaries secrete both estrogen
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...

 and progesterone
Progesterone
Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...

. Estrogen is responsible for the appearance of secondary sex characteristics of anatomically female people at puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...

 and for the maturation and maintenance of the reproductive organs in their mature functional state. Progesterone functions with estrogen by promoting menstrual cycle
Menstrual cycle
The menstrual cycle is the scientific term for the physiological changes that can occur in fertile women for the purpose of sexual reproduction. This article focuses on the human menstrual cycle....

 cyclic changes in the ndo

Ligaments

In the human the paired ovaries lie within the pelvic cavity, on either side of the uterus, to which they are attached via a fibrous cord called the ovarian ligament
Ovarian ligament
The ovarian ligament is a fibrous ligament that connects the ovary to the lateral surface of the uterus....

. The ovaries are uncovered in the peritoneal cavity
Peritoneal cavity
The peritoneal cavity is a potential space between the parietal peritoneum and visceral peritoneum, that is, the two membranes that separate the organs in the abdominal cavity from the abdominal wall...

 but are tethered to the body wall via the suspensory ligament of the ovary
Suspensory ligament of the ovary
The suspensory ligament of the ovary, also infundibulopelvic ligament , is a fold of peritoneum that extends out from the ovary to the wall of the pelvis....

. The part of the broad ligament of the uterus
Broad ligament of the uterus
The broad ligament of the uterus is the wide fold of peritoneum that connects the sides of the uterus to the walls and floor of the pelvis.-Subdivisions:The broad ligament may be divided into three subcomponents:...

 that covers the ovary is known as the mesovarium
Mesovarium
The mesovarium is the portion of the broad ligament of the uterus that covers the ovaries.At first the mesonephros and genital ridge are suspended by a common mesentery, but as the embryo grows the genital ridge gradually becomes pinched off from the mesonephros, with which it is at first...

. Thus, the ovary is the only organ in the human body which is totally invaginated into the peritonium, making it the only interperitoneal organ (not to be confused with intraperitoneal).

Extremities

There are two extremities to the ovary:
  • The end to which the uterine tube attaches is called the tubal extremity.
  • The other extremity is called the uterine extremity. It points downward, and it is attached to the uterus via the ovarian ligament.

Cell types

  • Follicular cells
    Ovarian follicle
    Ovarian follicles are the basic units of female reproductive biology, each of which is composed of roughly spherical aggregations of cells found in the ovary. They contain a single oocyte . These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single...

      flat epithelial cells that originate from surface epithelium covering the ovary
  • granulosa cells - surrounding follicular cells have changed from flat to cuboidal and proliferated to produce a stratified epithelium
  • Gametes

  • The outermost layer is called the ovarian surface epithelium (previously known as the germinal epithelium
    Germinal epithelium
    Germinal epithelium can refer to:* Germinal epithelium , a layer of cells covering the ovary* Germinal epithelium , a layer of cells covering the testicle* Germ layer, primary tissue layer formed during embryogenesis in animals...

    )
    .
  • The tunica albuginea
    Tunica albuginea (ovaries)
    On the surface of the ovary this tissue is much condensed, and forms a layer, the tunica albuginea, composed of short connective-tissue fibers, with fusiform cells between them.-External links:...

    covers the cortex.
  • The ovarian cortex
    Cortex (anatomy)
    In anatomy and zoology the cortex is the outermost layer of an organ. Organs with well-defined cortical layers include kidneys, adrenal glands, ovaries, the thymus, and portions of the brain, including the cerebral cortex, the most well-known of all cortices.The cerebellar cortex is the thin gray...

    consists of ovarian follicles and stroma
    Stroma of ovary
    The stroma of the ovary is a peculiar soft tissue, abundantly supplied with blood vessels, consisting for the most part of spindle-shaped cells with a small amount of ordinary connective tissue....

     in between them. Included in the follicles are the cumulus oophorus
    Cumulus oophorus
    The cumulus oophorus , also called discus proligerus, is a cluster of cells that surround the oocyte both in the ovarian follicle and after ovulation...

    , membrana granulosa
    Membrana granulosa
    The larger ovarian follicles consist of an external fibrovascular coat, connected with the surrounding stroma of the ovary by a network of bloodvessels; and an internal coat, which consists of several layers of nucleated cells, called the membrana granulosa...

     (and the granulosa cells inside it), corona radiata
    Corona radiata (embryology)
    The corona radiata surround an ovum or unfertilized egg cell, and consist of two or three strata of follicular cells. They are attached to the outer protective layer of the ovum, the zona pellucida, and their main purpose in many animals is to supply vital proteins to the cell...

    , zona pellucida
    Zona pellucida
    The zona pellucida is a glycoprotein membrane surrounding the plasma membrane of an oocyte. It is a vital constitutive part of the latter, external but of essential importance to it...

    , and primary oocyte. The zona pellucida, theca of follicle
    Theca of follicle
    The theca folliculi comprise a layer of the ovarian follicles. They appear as the follicles become tertiary follicles.The theca are divided into two layers, the theca interna and the theca externa....

    , antrum
    Follicular antrum
    The follicular antrum is the portion of an ovarian follicle filled with liquor folliculi.-External links: "Graafian Follicle" - "Mammal, canine ovary "*...

     and liquor folliculi are also contained in the follicle. Also in the cortex is the corpus luteum
    Corpus luteum
    The corpus luteum is a temporary endocrine structure in mammals, involved in production of relatively high levels of progesterone and moderate levels of estradiol and inhibin A...

     derived from the follicles.
  • The innermost layer is the ovarian medulla. It can be hard to distinguish between the cortex and medulla, but follicles are usually not found in the medulla.

In other animals

Ovaries of some kind are found in the female reproductive system of many animals that employ sexual reproduction
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...

, including invertebrates. However, they develop in a very different way in most invertebrates than they do in vertebrates, and are not truly homologous.

Many of the features found in human ovaries are common to all vertebrates, including the presence of follicular cells, tunica albuginea, and so on. However, many species produce a far greater number of eggs during their lifetime than do humans, so that, in fish and amphibians, there may be hundreds, or even millions of fertile eggs present in the ovary at any given time. In these species, fresh eggs may be developing from the germinal epithelium throughout life. Corpora lutea are found only in mammals, and in some elasmobranch fish; in other species, the remnants of the follicle are quickly resorbed by the ovary. In birds, reptiles, and monotreme
Monotreme
Monotremes are mammals that lay eggs instead of giving birth to live young like marsupials and placental mammals...

s, the egg is relatively large, filling the follicle, and distorting the shape of the ovary at maturity.

Amphibians and reptiles have no ovarian medulla; the central part of the ovary is a hollow, lymph
Lymph
Lymph is considered a part of the interstitial fluid, the fluid which lies in the interstices of all body tissues. Interstitial fluid becomes lymph when it enters a lymph capillary...

-filled space. The ovary of teleosts is also often hollow, but in this case, the eggs are shed into the cavity, which opens into the oviduct
Oviduct
In non-mammalian vertebrates, the passageway from the ovaries to the outside of the body is known as the oviduct. The eggs travel along the oviduct. These eggs will either be fertilized by sperm to become a zygote, or will degenerate in the body...

.

Although most normal female vertebrates have two ovaries, this is not the case in all species. In birds and platypus
Platypus
The platypus is a semi-aquatic mammal endemic to eastern Australia, including Tasmania. Together with the four species of echidna, it is one of the five extant species of monotremes, the only mammals that lay eggs instead of giving birth to live young...

es, the right ovary never matures, so that only the left is functional. In some elasmobranchs, the reverse is true, with only the right ovary fully developing. In the primitive jawless fish, and some teleosts, there is only one ovary, formed by the fusion of the paired organs in the embryo.

Cryopreservation

Cryopreservation
Cryopreservation
Cryopreservation is a process where cells or whole tissues are preserved by cooling to low sub-zero temperatures, such as 77 K or −196 °C . At these low temperatures, any biological activity, including the biochemical reactions that would lead to cell death, is effectively stopped...

 of ovarian tissue, often called Ovarian Tissue Cryopreservation, is of interest to women who want to preserve their reproductive function beyond the natural limit, or whose reproductive potential is threatened by cancer therapy, for example in hematologic malignancies or breast cancer. The procedure is to take a part of the ovary and carry out slow freezing before storing it in liquid nitrogen whilst therapy is undertaken. Tissue can then be thawed and implanted near the fallopian, either orthotopic (on the natural location) or heterotopic (on the abdominal wall),, where it starts to produce new eggs, allowing normal conception to take place. A study of 60 procedures concluded that ovarian tissue harvesting appears to be safe. The ovarian tissue may also be transplanted into mice that are immunocompromised (SCID mice) to avoid graft rejection, and tissue can be harvested later when mature follicles have developed.

External links


See also

  • Ovarian reserve
    Ovarian reserve
    Ovarian reserve is a term that is used to determine the capacity of the ovary to provide eggs that are capable of fertilization resulting in a healthy and successful pregnancy...

  • Folliculogenesis
    Folliculogenesis
    In biology, folliculogenesis is the maturation of the ovarian follicle, a densely-packed shell of somatic cells that contains an immature oocyte...

  • Ovarian disease
    Ovarian disease
    Ovarian diseases can be classified as endocrine disorders or as a disorders of the reproductive system.If the egg fails to release from the follicle in the ovary an ovarian cyst may form. Small ovarian cysts are common in healthy women...

  • Oophorectomy
    Oophorectomy
    Oophorectomy is the surgical removal of an ovary or ovaries. The surgery is also called ovariectomy, but this term has been traditionally used in basic science research describing the surgical removal of ovaries in laboratory animals...

  • Menopause
    Menopause
    Menopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...

  • Ovum
    Ovum
    An ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK