1.1 The Female Reproductive System
The female reproductive system is a complex system of several organs that produces egg cells and nourishes and protects the developing embryo. Using the diagram below as a guide, familiarize yourself with the main parts of the female reproductive system discussed below.
- The vagina is a musculomembranous canal that is the sexual organ in the female. It extends from the cervix of the uterus to the exterior of the body. The cervix is the narrow opening of the uterus.
Figure 1.1 The Female Reproductive System
- The uterus is a muscular, hollow pear-shaped organ in the lower pelvis that is home to the embryo, which develops into a fetus during pregnancy. Upon fertilization, the egg develops into an embryo. It attaches to and is nourished by the lining of the uterus, the endometrium. The endometrium is composed of mucous membrane influenced by estrogen and progesterone hormones. It grows and becomes thick each month with the capability to support a pregnancy. If pregnancy does not occur, the thickened lining is shed during a process called menstruation.
- The fallopian tubes are 3-4 inch tubes extending from the upper sides of the uterus to just above the ovaries. The tubes form a passageway between the uterus and the ovaries in which the egg and sperm meet and fertilization can occur. Extending from each tube, just above the ovary, are fingerlike projections called the fimbriae, which catch the egg released by the ovary to be drawn up into the tube.
- The ovaries are home to a woman's lifetime reserve of eggs. By the time a female begins her menstrual cycle; her egg reserve has decreased from several million at birth to about 400,000. As a woman ages, her egg reserve continues to diminish and by menopause, her reserve is depleted. During each cycle, several eggs mature in the ovaries in fluid-filled sacs called follicles. Each month, one "dominant follicle" ruptures, releasing a single egg, which is drawn into the fallopian tube for possible fertilization (see Figure 1.2).
Figure 1.2 Structure of the egg: The monthly
"dominant follicle" ruptures releasing a single egg.