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Encyclopedia > Corpus luteum

The corpus luteum (Latin for "yellow body") is a small, temporary endocrine structure in animals. It develops from an ovarian follicle during the luteal phase of the estrous cycle, following the release of a mature egg from the follicle during ovulation. While the egg traverses the Fallopian tube into the uterus, the corpus luteum remains in the ovary. Image File history File links Illu_ovary_2. ... Image File history File links Illu_ovary_2. ... Latin is an ancient Indo-European language. ... The endocrine system is a control system of ductless endocrine glands that secrete chemical messengers called hormones that circulate within the body via the bloodstream to affect distant organs. ... Phyla Subregnum Parazoa Porifera (sponges) Subregnum Agnotozoa Placozoa (trichoplax) Orthonectida (orthonectids) Rhombozoa (dicyemids) Subregnum Eumetazoa Radiata (unranked) (radial symmetry) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Bilateria (unranked) (bilateral symmetry) Acoelomorpha (basal) Myxozoa (slime animals) Superphylum Deuterostomia (blastopore becomes anus) Chordata (vertebrates, etc. ... Ovarian follicles or Graafian follicles (after Regnier de Graaf) are the roughly spherical cell aggregations in the ovary containing an ovum and from which the egg is released during ovulation. ... The luteal phase is the latter phase of the estrous cycle in animals. ... The estrus cycle (also Å“strus or estrous cycle) refers to the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females (humans and great apes are the only mammals who undergo a menstrual cycle instead). ... A human ovum Sperm cells attempting to fertilize an ovum An ovum (plural ova) is a haploid female reproductive cell or gamete. ... Ovulation is the process in the menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum (also known as an oocyte, female gamete, or casually, an egg) that participates in reproduction. ... Female internal reproductive anatomy The Fallopian tubes or oviducts are two very fine tubes leading from the ovaries of female mammals into the uterus. ... The uterus or womb is the major female reproductive organ of most mammals, including humans. ... Human female internal reproductive anatomy Ovaries are egg-producing reproductive organs found in female organisms. ...


Function

It is essential for establishing and maintaining pregnancy in females. In the ovary, the corpus luteum secretes progesterone, which is a steroid hormone responsible for the thickening of the endometrium and its development and maintenance, respectively. If the egg is not fertilized, the corpus luteum stops secreting progesterone and decays (after approximately 14 days in humans). It then degenerates into a corpus albicans, which is a mass of fibrous scar tissue. The uterine lining sloughs off without progesterone and is either resorbed (in most animals) or expelled through the vagina (in humans and some great apes). The latter is called menstruation. Progesterone is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. ... Steroid hormones are steroids which act as hormones. ... The endometrium is the inner uterine membrane in mammals which is developed in preparation for the implantation of a fertilized egg upon its arrival into the uterus. ... The corpus luteum (Latin for yellow body) is a small, temporary endocrine structure in mammals that develops from an ovarian follicle after it has released a mature egg. ... A hypertrophic scar on the ilium of the pelvis Both hypertrophic and keloid scars are more common on younger and darker skinned people. ... The vagina, (from Latin, literally sheath or scabbard ) is the tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. ... The menstrual cycle is the periodic change in a womans body that occurs every month between puberty and menopause and that relates to reproduction. ...


If fertilized, however, the placenta secretes the hormone human chorionic gonadotropin (hCG) or a similar hormone in other species. This hormone signals the corpus luteum to continue progesterone secretion, thereby maintaining the thick lining (endometrium) of the uterus, and providing an area rich in blood vessels in which the zygote(s) can develop. From this point on, the corpus luteum is called the corpus luteum graviditatis. The introduction of the hormone prostaglandin at this point causes the degeneration of the corpus luteum and the abortion of the fetus. However, in placental animals such as humans the placenta eventually takes over progesterone production and the corpus luteum degrades into a corpus albicans without embryo/fetus loss. Human chorionic gonadotropin (hCG) is a peptide hormone produced in pregnancy, that is made by the embryo soon after conception and later by the trophoblast (part of the placenta). ... The arterial system The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... This article or section does not cite its references or sources. ... Chemical structure of prostaglandin E1 (PGE1). ... Fetus at eight weeks For other uses, see Fetus (disambiguation). ... The placenta is an ephemeral (temporary) organ present only in female placental mammals during gestation (pregnancy). ... The corpus luteum (Latin for yellow body) is a small, temporary endocrine structure in mammals that develops from an ovarian follicle after it has released a mature egg. ...


Structure

The corpus luteum is typically very large relative to the size of the ovary; in humans, the size of the structure ranges from under 2 cm to 6 cm in diameter. [1] Its cells develop from the follicular cells surrounding the ovarian follicle. The granulosa cells become the outer granulosa lutein layer and secrete progesterone. Theca interna cells become the inner theca lutein layer which secretes estrogen.


Reference

  • Bagnell, C. 2005. "Animal Reproduction". Rutgers University Department of Animal Sciences.

The granulosa cells which are stimulated by FSH mainly secrete estrogen whereas Theca interna cells are stimulated by LH to produce androstenedione, which via a few steps, gives the granulosa the precursor for estrogen manufacturing. (Boron & Boulpeap Medical Physiology updated edition 2005 p1153-1155)


  Results from FactBites:
 
Corpus luteum - definition of Corpus luteum in Encyclopedia (239 words)
The corpus luteum (Latin for "yellow body") is a small, temporary endocrine structure in mammals that develops from an ovarian follicle after it has released a mature egg.
The corpus luteum secretes the hormone progesterone, which thickens the uterine lining in preparation for the fertilized egg.
From this point on, the corpus luteum is called the corpus luteum graviditatis.
  More results at FactBites »

 
 

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