Female Reproductive System Anatomy and Physiology

Overview of the Female Reproductive System

The primary functions of the female reproductive system are to produce offspring for genetic continuity, produce eggs ($female\,gametes$), and provide nutrition and protection to the offspring for several years after conception.

Structural Plan

Essential Organs

• Gonads: Paired ovaries.

• Gametes: Ova produced by the ovaries.

Accessory Organs

• Internal Genitals: Uterine tubes, uterus, and vagina.

• External Genitals: The vulva.

• Additional Glands: Mammary glands.

Perineum

The skin-covered region located between the vaginal orifice and the rectum; this area is susceptible to tearing during childbirth.

Ovaries

• Location: Nodular glands on each side of the uterus, below and behind the uterine tubes.

• Structure: Covered by germinal epithelium; contains ovarian follicles where female sex cells develop.

• Functions:

  • Oogenesis: The process of forming a mature egg ($ovum$).

  • Endocrine Secretion: Production of $\text{estrogens}$ and $\text{progesterone}$.

Uterus

• Structure: Pear-shaped organ consisting of the fundus (bulging upper part), the body, and the cervix (lower part).

• Wall Layers:

  • Endometrium: Inner mucous membrane.

  • Myometrium: Middle smooth muscle layer.

  • Perimetrium: Outer layer of parietal peritoneum.

• Functions: Facilitates sperm ascent, provides environment for fetal development (via the placenta), and triggers labor through myometrial contractions. If no conception occurs, the outer layers of the endometrium are shed during menstruation.

Uterine Tubes

Also known as fallopian tubes or oviducts, these consist of Three divisions: isthmus, ampulla, and infundibulum. They serve as transport channels for ova and are the primary site of fertilization.

Vagina and Vulva

• Vagina: A collapsible tube lined with rugae. It serves as a receptacle for semen, the lower birth canal, and the transport path for menstrual tissue.

• Vulva (Pudendum): Includes the mons pubis, labia majora, labia minora, clitoris, urinary meatus, vaginal orifice, and greater vestibular glands.

Female Reproductive Cycle

• Endometrial (Menstrual) Cycle Phases: Menses, Postmenstrual phase (proliferative phase), Ovulation, and Premenstrual phase.

• Hormonal Control: Cyclical changes are regulated by the hypothalamus and pituitary gonadotropins ($FSH$ and $LH$), which in turn control ovarian secretion of $\text{estrogens}$ and $\text{progesterone}$.

• Key Event: Regression of the corpus luteum (if pregnancy does not occur) causes a drop in hormone levels, leading to endometrial sloughing.

Breasts and Lactation

• Structure: Composed of lobes and lobules containing milk-secreting pouches called alveoli. Lactiferous ducts carry milk to the nipple.

• Hormonal Control:

  • Development: $\text{Estrogens}$ and $\text{progesterone}$.

  • Lactation Stimulation: Prolactin.

  • Milk Ejection: Oxytocin.

• Importance: Provides nutrients, passive immunity via colostrum and milk, and emotional bonding.

Questions & Discussion

• What are the essential organs of the female reproductive system? The ovaries (gonads).

• List the major accessory organs of the female reproductive system? Uterine tubes, uterus, vagina, vulva, and mammary glands.

• Briefly describe the location of the ovaries? They are nodular glands located on each side of the uterus, below and behind the uterine tubes.

• What are ovarian follicles? Structures within the ovaries that contain developing female sex cells.

• List the two major functions of the ovaries? Oogenesis (egg formation) and secretion of hormones ($\text{estrogens}$ and $\text{progesterone}$).

• Name the three principal layers of the uterine wall? Endometrium, myometrium, and perimetrium.

• Describe the anatomical position of the uterus? How is it held in place? It is located in the pelvic cavity between the bladder and rectum; it is held in place by several ligaments.

• List the chief functions of the uterus? Sperm transport, fetal development, placenta formation, labor contractions, and menstruation.

• What are the functions of the uterine tubes? Transport channels for ova and the site of fertilization.

• List three functions of the vagina? Receptacle for semen, lower birth canal, and transport of menstrual flow.

• What is another name for the external genitals of the female? The vulva or pudendum.

• How are the clitoris of the female and the glans penis of the male similar in structure and function? Both contain sensory receptors involved in the sexual response.

• What is the function of the corpus luteum? To secrete hormones (estrogen and progesterone) that maintain the uterine lining.

• How is the corpus luteum formed? It forms from the remnants of an ovarian follicle after ovulation.

• What is the difference between the ovarian cycle and the menstrual cycle? The ovarian cycle refers to events in the ovaries (follicle development and ovulation), while the menstrual cycle refers to the cyclical changes in the uterine endometrium.

• Why is the postmenstrual phase of the menstrual cycle sometimes called the proliferative phase? Because the endometrial lining is regenerating and thickening (proliferating).

• A surge of FSH and LH is associated with what major event of the ovarian cycle? Ovulation.

• How does an increase in estrogen level affect the uterine lining? It causes the endometrium to thicken and its glands to grow.

• What is menopause? What causes menopause to occur? The cessation of the menstrual cycle, typically occurring after about three decades of fertility, caused by the decrease in ovarian function and hormone production.

• Briefly describe the network of ducts and secreting cells that form the mammary glands? Milk is produced in pouches called alveoli, which are organized into lobules and lobes; lactiferous ducts then carry the milk to the nipple.

• List the hormones that prepare the breast structurally for lactation? $\text{Estrogens}$ and $\text{progesterone}$.

• Which hormone causes milk to be ejected into the lactiferous ducts? Oxytocin.