Ovary

From IKE
Jump to: navigation, search
Uterus and right broad ligament, seen from behind.

In the adult, the ovaries are roughly almond-shaped, with irregular surfaces. Each one lies against the lateral wall of the pelvis, in a fossa. During ovulation, released oocytes are directed into the opening of the uterine tube by the fimbriae. Each ovary is attached to the wall of the uterus via the (round) ligament of the ovary, a remnant of the gubernaculum. The ovary consists of an outer cortex, which contains developing ovarian follicles, and an inner medulla. Ovaries create ova through oogenesis.

Section of the ovary

Histology

When a woman is pregnant, her corpus luteum enlarges to an obscene extent, eventually making up the majority of the ovary. When the woman gives birth, the corpus luteum becomes a corpus albicans. Each corpus albicans indicates one pregnancy / birth.

Hypothalamic-pituitary control of ovarian function

Objectives

  1. Gamete Transport and Maturation in the Female Reproductive Tract
    • Describe egg transport from the ovulated follicle to the site of fertilization
    • Describe sperm transport from the vagina to the site of fertilization
    • State the functional changes in the sperm during this time.

Anatomy

  • Give a general description of the gross and micro-anatomical features of the ovary and how these features change during one ovarian cycle

Chemistry and Secretion of Steroid Hormones

  • Identify the major steroid products of the ovary and state the ovarian site of production
  • Compare and contrast steroidogenesis in the ovary and testis

Release, Transportation and Inactivation

  • Describe how the ovarian hormones leave their cells of production and how they are transported in plasma
  • Describe the cellular mechanism of action of the ovarian steroid hormones
  • State how the ovarian steroids are inactivated

Endocrine Regulation of the Ovarian Cycle

  • List the hypothalamic and pituitary hormones involved in ovarian function, describe their chemical nature, state the cell type on which each hormone acts, and describe their mechanism of action
  • Draw a graph showing the changes in ovarian and pituitary hormones which occur during a normal menstrual cycle and describe how this cyclic behavior is regulated

Physiologic Effects of the Ovarian Steroids

  • Cite organs that are sensitive to progesterone and estradiol and state what functions of those organs are supported by the ovarian steroids


Gamete transport and maturation

  • Describe egg transport from the ovulated follicle to the site of fertilization
  • After ovulation the oocyte, surrounded by a mass of cumulus oophorous cells, is "picked up" by the fimbria of the fallopian tube
  • This action requires the motion of fimbrial cilia to remove the cumulus mass from the site of follicle rupture
  • These cilia also propel the mass along through the ostium and into the ampulla of the oviduct
  • The density of cilia in the fimbria is dependent on circulating estrogen concentration
  • Further movement of the cumulus mass is achieved by ciliary motion and smooth muscle contraction
  • Pharmacologic blockade of smooth muscle activity does not slow the progress of the oocyte, thus ciliary motion may be more important and muscle activity a "redundant" mechanism
  • Upon reaching the ampulla, the cumulus mass is held up for several hours
  • If sperm are present, fertilization will occur at this time and the early stages of development will occur.
  • Also see Sperm

Resources