7.5: Physiology of the Female Reproductive System
Menstruation (men-strŪ-Ā-shŏn), also called menses, commonly referred to as a woman’s “period,” is vaginal bleeding that occurs as part of a monthly cycle. Every month, the female body prepares for possible pregnancy. If no pregnancy occurs, the uterus sheds the endometrial lining. Menstrual flow is part blood and part endometrial lining that passes out of the uterus, through the cervix, and into the vagina. Menstruation typically starts in females between the ages of 11 and 14 and continues until menopause at an average age of 51. In addition to bleeding, females may experience additional emotional and physical symptoms, which is referred to as premenstrual syndrome (PMS). [1] Premenstrual syndrome (PMS) is discussed in more detail in the “Diseases and Disorders of the Female Reproductive System” section of this chapter.
The Menstrual Cycle
The menstrual cycle is driven by a monthly hormonal cycle as the female’s body prepares an egg for fertilization and possible pregnancy. The menstrual cycle is counted from the first day of a bleeding of one cycle to the first day of the next menstrual cycle. Menstrual flow usually lasts about three to five days. The typical volume of blood lost during menstruation is approximately 30 milliliters (mL). Amounts greater than 80 mL, menstrual flow longer than five days, or bleeding between cycles can be symptoms of a disorder. [2]
The average menstrual cycle takes about 28 days and occurs in three phases, called the follicular, ovulatory, and luteal phases, also referred to as menses, proliferative, and secretory uterine cycles. Hormone levels change throughout the menstrual cycle. See Figure 7.4 for an illustration of the phases of the menstrual cycle. [3]
Other Medical Terms Related to the Female Reproductive System
- Adnexa (ăd-NĔK-să): Accessory structures of the uterus, such as the Fallopian tubes and ovaries.
- Amenorrhea (ā-men-ŏ-RĒ-ă): Absence of menstrual flow.
- Anovulation (an-ov-yŭ-LĀ-shŏn): Absence of ovulation.
- Contraception (kon-tră-SEP-shŏn): Intentional prevention of pregnancy.
- Dysmenorrhea (dis-men-ŏ-RĒ-ă): Painful menstrual flow.
- Dyspareunia (dis-pă-RŪ-nē-ă): Painful sexual intercourse.
- Fistula (FIS-chŭ-lă): An abnormal passageway between two organs or an internal organ and the body surface. Although uncommon, a vaginal fistula can develop between the vagina and another organ, such as the urinary bladder, colon, or rectum.
- Infertility (ĭn-fĕr-TĬL-ĭ-tē): The inability to conceive.
- Mastitis (mas-TĪT-ĭs): Inflammation of the breast that tends to occur when a woman is lactating.
- Menorrhagia (mĕn-ō-RĀ-jē-ă): Excessive menstrual bleeding.
- Menometrorrhagia (mĕn-ō-mĕt-rō-RĀ-jē-ă): Excessive and prolonged uterine bleeding occurring at irregular and/or frequent intervals.
- Metrorrhagia (mē-trō-RĀ-jă): Bleeding from the uterus between menstrual periods.
- Menarche (mĕn-ĂR-kē): The first occurrence of menstruation.
- Oligomenorrhea (ŏl-ĭ-gō-mĕn-ō-RĒ-ă): Infrequent or very light menstruation.
- Polymenorrhea (pŏl-ē-mĕn-ō-RĒ-ă): Frequent menstruation in which menstrual cycles are shorter than 21 days in length.
- Sexual intercourse (Sĕk-shū-ăl ĭn-tĕr-kōrs): Sexual contact between individuals that includes insertion of a penis into a vagina.
- Tubal ligation (TOO-băl lī-GĀ-shŏn): Surgical closure or blocking of the Fallopian tubes to prevent pregnancy; also referred to as sterilization.
- Anatomy & Physiology by OpenStax is licensed under CC BY 4.0. Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction ↵
- Anatomy & Physiology by OpenStax is licensed under CC BY 4.0. Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction ↵
- “ MenstrualCycle2_en.svg.png ” by Isometrik is licensed under CC BY 3.0 ↵
- Cleveland Clinic. (2022, November 28). Female reproductive system . my.clevelandclinic.org/health/articles/9118-female-reproductive-system ↵
- Cleveland Clinic. (2022, November 28). Female reproductive system . my.clevelandclinic.org/health/articles/9118-female-reproductive-system ↵
- Cleveland Clinic. (2022, November 28). Female reproductive system . my.clevelandclinic.org/health/articles/9118-female-reproductive-system ↵
- “ Anatomy_and_physiology_of_animals_Ovarian_cycle_showing_from_top_left_clockwise.jpg ” by Sunshineconnelly at English Wikibooks is licensed under CC BY 3.0 ↵
- A.D.A.M. (2022, January 10). Ovulation [Video]. Medline Plus. https://medlineplus.gov/ency/anatomyvideos/000094.htm ↵