Corpus Luteum - Anatomy & Physiology

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The Corpus Luteum

  • When the dominant antral follicle ovulates, slight localised haemorrhage occurs at the site of ovulation and fills the former cavity.
  • The small amount of bloody tissue can be observed by the naked eye.
  • Loss of fluid from the antral cavity causes the follicle to collapse into many folds.
  • As a result, some granulosal and thecal layers are pushed into the apex of the ruptured follicle.
  • This protrusion of tissue and ruptured blood vessels forms a structure known as the Corpus Haemorrhagicum.
  • Following this, the theca interna and granulosa cells differentiate into large and small luteal cells.
    • Luteal cells contain increased quantities of lipid droplets and the pigment 'lutein'.
  • As the blood is resorbed, a solid Corpus Luteum is formed by proliferation of granulosa and theca intera cells as well as blood vessels. This remains on the surface of the ovary.
  • In the non-pregnant animal, corpora lutea are transient structures.
  • Cyclic corpora lutea undergo proliferation and vascularisation directly after ovulation.
  • The corpora lutea then regress and degenerate into a connective tissue scar, the Corpus Albicans.
  • If the ovum is fertilised, the corpus luteum remains fully developed and active throughout at least part of the pregnancy.
  • Corpora lutea produce progesterone.
  • Progesterone prepares and maintains the uterus for implantation of the fertilised ovum.
  • The number of corpora lutea formed are directly related to the number of oocytes released.

Control of Progesterone Biosynthesis in the Corpus Luteum

Progesterone Biosynthesis- Copyright L.Wilkie 2008
  • In most species, luteinization and progesterone synthesis is regulated principally by luteinising hormone (LH) in the non-fertile cycle.
  • Further conversion to oestradiol is prevented.


Corpus Luteum Formation

=== Corpus Luteum Regression ===