Ovary

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Ovary
Internal reproductive organs of human female
Latin ovarium
Gray's subject #266 1254
Artery ovarian artery, uterine artery
Vein ovarian vein
Lymph lumbar lymph nodes
MeSH Ovary
Dorlands/Elsevier o_09/12603251
For ovary as part of plants see ovary (plants)

Ovaries are egg-producing reproductive organs found in female organisms. They are part of the vertebrate female reproductive system. Ovaries in females are homologous to testes in males. The term gonads refers to the ovaries in females and testes in males.

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[edit] Production of eggs (exocrine)

As female mammals develop within the womb, each ovary develops a number of immature eggs associated with groups of other cells called follicles. While mammals were thought to develop their entire supply of eggs prenatally and soon after birth, new evidence from laboratory mice has called this into question, showing that female mice in fact produce new eggs throughout their reproductive lifetime. However, there is no direct evidence showing that human females produce new eggs after birth. As the animal becomes reproductively mature (the process called puberty in humans), eggs will periodically mature and be released from the ovary (a process called ovulation) so that they will be available for fertilization by sperm. A fertilized egg resulting from union with a sperm becomes a zygote and then an embryo as it develops.

In humans, an egg launched from an ovary has to traverse a slight space before entering the fallopian tube and moving gradually down to the uterus. If fertilized, it implants itself into the lining of the uterus and develops as the pregnancy continues. If the fertilized egg settles into the fallopian tube instead of the uterus an ectopic pregnancy will result. Ectopic pregnancy can also happen if a fertilized egg settles onto the cervix or onto the ovary itself, or if a fertilized egg passes through the gap between the ovary and the fallopian tube into the abdomen.

[edit] Hormone secretion (endocrine)

Animal and human ovaries also produce various steroid and peptide hormones. Estrogen and progesterone are the most important of these in mammals.

These hormones serve many functions:

[edit] Human anatomy

Ovaries are oval shaped and, in the human, measure approximately 3 cm x 1.5 cm x 1.5 cm. 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.

[edit] 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.

[edit] 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.

[edit] Vessels and nerves

Each ovary receives blood from the ovarian artery, which arises directly from the abdominal aorta on the right side and from the renal artery on the left side. The right ovarian vein drains to the inferior vena cava and the left ovarian vein drains to the left renal vein- and the ovarian branch of the uterine artery that enters the ovary by way of the broad ligament and thus the mesovarium. It is drained by the ovarian vein. The artery and vein are covered by the suspensory ligament of the ovary. The artery and vein arise from the tubal extremity. Sources of innervation include the ovarian plexus.

[edit] Histology

[edit] Pathology

[edit] Additional images

[edit] External Links

[edit] See also

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