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"Ovaria" redirects here. This is also a proposed section and a synonym of Solanum.
Ovary
Female anatomy.png
Internal reproductive organs of human female
Latin ovarium
Gray's subject #266 1254
Artery ovarian artery, uterine artery
Vein ovarian vein
Nerve ovarian plexus
Lymph lumbar lymph nodes
MeSH Ovary
Dorlands/Elsevier Ovary

The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in females are homologous to testes in males, in that they are both gonads and endocrine glands.

Contents

Human anatomy

Ovaries are oval shaped and, in the human, measure approximately 3 cm x 1.5 cm x 1.5 cm (about the size of a Greek olive). The ovary (for a given side) is located in the lateral wall of the pelvis in a region called the ovarian fossa. The fossa usually lies beneath the external iliac artery and in front of the ureter and the internal iliac artery.

The ovaries aren't attached to the fallopian tubes but to the outer layer of the uterus 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 and progesterone. Estrogen is responsible for the appearance of secondary sex characteristics of females at puberty and for the maturation and maintenance of the reproductive organs in their mature functional state. Progesterone functions with estrogen by promoting cyclic changes in the endometrium (it prepares the endometrium for pregnancy), as well as by helping maintain the endometrium in a healthy state during pregnancy.

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. The ovaries are uncovered in the peritoneal cavity but are tethered to the body wall via the suspensory ligament of the ovary. The part of the broad ligament of the uterus that covers the ovary is known as the mesovarium. 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 attach 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.

Histology

Cell Types

  • Follicular Cells flat epithelial cells that originate from surface epithelium covering the ovary
  • granulosa cells - surrounding follicular cells have change from flat to cuboidal and proliferated to produce a stratified epithelium
  • Gametes[1]
Section of the ovary of a newly born child. Germinal epithelium is seen at top. Primitive ova are seen in their cell-nests. The Genital cord or genital ridge is still discernible in this young child. A blood vessel and an ovarian follicle is also seen

In other animals

Ovaries of some kind are found in the female reproductive system of many animals that employ sexual reproduction, including invertebrates. However, they develop in a very different way in most invertebrates than they do in vertebrates, and are not truly homologous.[2]

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 monotremes, the egg is relatively large, filling the follicle, and distorting the shape of the ovary at maturity.[2]

Amphibians and reptiles have no ovarian medulla; the central part of the ovary is a hollow, lymph-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.[2]

Although most normal female vertebrates have two ovaries, this is not the case in all species. In birds and platypuses, 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.[2]

Additional images

References

  1. ^ Langman's Medical Embryology, Lippincott Williams & Wilkins, 10th ed, 2006
  2. ^ a b c d Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. pp. 383-385. ISBN 0-03-910284-X. 

External links

  • [1] From the American Medical Association
  • [2] Merck Online Medical Library: Female Reproductive System

See also


Simple English

Ovary
Latin ovarium
Gray's subject #266 1254
Artery ovarian artery, uterine artery
Vein ovarian vein
Nerve ovarian plexus
Lymph lumbar lymph nodes
MeSH Ovary
Dorlands/Elsevier o_09/12603251

Ovaries (Singular: Ovary) are organs found in female organisms. Ovaries are part of the reproductive system needed to reproduce sexually.

Most vertebrates have ovaries. Usually animals have two ovaries. Birds usually have only one working ovary, snakes have one ovary in front of the other. The ovaries are similar to testicles in men.

Contents

Anatomy

Ovaries are shaped like eggs and are around 3 cm by 1.5 cm by 1.5 cm. The ovary is found in the side walls of the pelvis.

Each ovary is attached to the Fallopian tube. Usually each ovary takes turns releasing eggs every month.

Uses

Ovaries have two purposes:

Menstruation

During menstruation, a ovum is released from the ovary to be fertilised. Ovaries have a certain number of eggs in them, so when eggs stop being released, this is the start of the menopause. During this time, female hormones stop being produced.

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