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Living Well with Endometriosis

HarperCollins Publishers, Inc.

Let's start at the beginning. In order to better understand living with endometriosis, you need to educate yourself about the disease. In this chapter you will learn about endometriosis's association with your reproductive system, how it looks, and where in your body the disease often manifests itself. Additionally, the chapter will review the prevalence of the disease and the costs of treatment, and will present an overview on how endometriosis is diagnosed and treated.

The Female Reproductive System

The primary structures in the female reproductive system are the following:

• Uterus: A pear-shaped organ settled between the lower intestine and the bladder. The uterus has two parts: the body and the cervix.
• Body: This section of the uterus is about the size of a fist when a woman is not pregnant. In this state the uterine walls are flattened against each other. The walls push apart during pregnancy as the fetus grows.
• Cervix: This is the base of the uterus that opens into the vagina. This opening, called theos, allows menstrual blood to flow out of the uterus and into the vagina.
• Fallopian tubes: These two tubes lead off each side of the body of the uterus. Each tube is about 4 inches (10 centimeters) long. At the end of each is an ovary.
• Ovaries: A woman's eggs are produced in these two ovaries. Each ovary is about 1.25 inches (3 centimeters) long and 0.75 inch (2 centimeters) wide and contains between 200,000 and 400,000 follicles or sacs. These contain the materials needed to reproduce ripened eggs or ova.
• Endometrium: This is the inner lining of the walls of the uterus. "Endo" is Greek for inside and "metrium" is Greek for uterus. During the menstrual cycle it becomes enriched with blood vessels and thickens, preparing for a possible pregnancy. If pregnancy does not occur, it is shed and flows out of the uterus and into the vagina, along with blood and mucus from the cervix, as menstruation.

The Menstrual Cycle

The menstrual cycle varies for many women, but twenty-eight days is generally the normal cycle. During ovulation, the process of discharging a mature egg or ovum, the female body develops and releases one or more eggs. The inner lining of the uterus thickens and becomes enriched with blood vessels to prepare for the possible implantation of a fertilized egg and to support the developing fetus. If fertilization and pregnancy do not occur, the uterus sheds the endometrial lining, and a new menstrual cycle begins.

Shedding of the endometrial lining is called menstruation. This menstrual bleeding -- menses or period -- can last five to seven days and present symptoms such as cramping, bloating, nausea, diarrhea, constipation, breast tenderness, headaches, irritability, and other mood changes.

The Endocrine System and the Menstrual Cycle

The endocrine system is the control panel for many of the body's functions. It is made up of several glands and the hormones they release, which influence various functions such as ovulation and menstruation. The major endocrine glands are the hypothalamus, pituitary, thyroid, parathyroids, adrenals, pineal body, and the ovaries.

The menstrual cycle is closely regulated by three major glands in the endocrine system. These are the hypothalamus (a region in the brain), the pituitary gland (at the base of the brain), and the ovaries (the main female reproductive organ). The hypothalamus controls the hormonal secretions from the pituitary gland, either stimulating or suppressing hormone secretions. The pituitary gland is considered the most important part of the endocrine system. Often referred to as the "master gland," it produces and secretes into the bloodstream hormones that control several other endocrine glands such as the ovaries. The ovaries also produce their own hormones in response to hormonal stimulation from the pituitary gland, which are involved in the menstrual cycle.

Hormones of the Menstrual Cycle

There are six key hormones in the menstrual cycle.

Gonadotrophin Releasing Hormone (GnRH)

This hormone is released by the hypothalamus to stimulate the pituitary gland in a series of pulses or positive and negative feedback loops to release the follicle-stimulating hormone (FSH) and luteinizing hormone (LH) into the bloodstream.

Follicle-Stimulating Hormone (FSH)

FSH and a little LH are secreted by the pituitary gland into the bloodstream to trigger the onset of ovulation. Under the influence of FSH, a number of immature follicles grow to maturity. The maturing follicles in turn produce estradiol, a powerful form of estrogen that prepares the endometrial lining for a possible pregnancy. This is called the follicular phase of the menstrual cycle.

Estrogen

The estrogen produced by the maturing follicles, estradiol, initiates the development of a new layer of endometrium (the inner lining of the uterus) to accommodate the possible implantation of a fertilized egg. As the follicles continue to ripen, they secrete more and more estradiol into the bloodstream until it reaches a certain point. At this point the estrogen sends a negative feedback loop to the pituitary gland to reduce secretion of FSH. The largest follicle secretes inhibin, which also reduces the secretion of FSH to the follicles. Testosterone is also released by the ovaries in small amounts.

Luteinizing Hormone (LH)

When the follicle has fully matured, it secretes enough estradiol into the bloodstream to cause the hypothalamus to release luteinizing hormone releasing factor (LHRF). This stimulates the pituitary gland to release a large amount of LH to begin the luteal phase of the menstrual cycle. This LH surge weakens the follicular wall and releases the now mature egg.

Progesterone

After ovulation the burst follicle remains in the ovary to form the corpus luteum (Latin for "yellow body"), which secretes estradiol and, in larger amounts, progesterone. This hormone prepares the inner lining (endometrium) of the uterus for pregnancy. If fertilization and implantation do not occur, progesterone levels fall, leading to the breakdown of the endometrial lining and shedding (menses or period).

A Word About Estrogen and Progesterone

The two major hormones in females are estrogen and progesterone. Estrogen is the umbrella name for a group of hormones that control female sex organs and secondary sexual characteristics. The three major human estrogens are estradiol, estrone, and estriol. One of the primary functions of estrogen is to control the development of the uterus. And, as we learned above, estrogen specifically initiates the development of the endometrium for possible pregnancy. Estrogen, therefore, stimulates cell growth.

Continues...

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Excerpted from Living Well with Endometriosis by Kerry-Ann Morris Copyright ©2006 by Kerry-Ann Morris. Excerpted by permission.
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