Female Reproductive System – Anatomy & Physiology

Female reproductive system is divided into:
- Internal organs: ovaries, oviducts (uterine / fallopian tubes), uterus, vaginal canal
- External genitalia: vulva (not elaborated in detail here but acknowledged)
Functional goals
- Produce eggs (oocytes)
- Secrete estrogen (and other hormones)
- Support, nourish, and protect a developing fetus after fertilization
- Coordinate menstruation when fertilization does not occur
Orientation cues used in lecture/figures
- Anterior landmarks: pubic symphysis, urinary bladder
- Posterior landmark: sacrum (and rectum)
- View described as “looking down into the pelvis”

Shape & position
- Two almond-shaped glands, left & right of uterus, just inferior to the uterine tubes
Internal micro-architecture
- Ovarian follicles: each contains an immature egg (oocyte)
- Ovulation
- Definition: release of a mature egg from follicle
- Frequency: approximately every $28$ days (average ovarian cycle length)
- Ovarian (menstrual) cycle stages
- Developing (growing) follicle ➔ Ovulation event ➔ Post-ovulation structure called corpus luteum
- Corpus luteum functions
  - Secretes hormones (progesterone, estrogen) to maintain early pregnancy if fertilization succeeds
  - If no fertilization, degenerates/disintegrates ➔ hormone levels fall ➔ menstruation begins

Links ovaries to uterus; paired structures on each side
Three named anatomical regions (lateral ➔ medial)
1. Infundibulum (funnel-shaped distal end)
- Bears fimbriae (finger-like projections)
  - Hover over, but do not touch, ovary (small gap present)
  - Function: sweep/capture ovulated egg into tube opening
1. Ampulla (wide, central region)
- Typical site of fertilization
- Mucosal lining nourishes resulting zygote during early cell divisions
1. Isthmus (narrow portion adjacent to uterus)
- Delivers egg or zygote into uterine cavity
Histological layers (from outside in)
1. Serous coat (peritoneal covering)
2. Muscular coat — smooth muscle, produces peristaltic contractions
3. Mucosal layer — ciliated epithelium + secretory cells
- Cilia & muscular contractions cooperate to move the ovum/zygote
Fate of transported ovum
- Fertilized: enters uterus for implantation
- Not fertilized: enters uterus and is expelled during menstruation

General description: hollow, thick-walled, muscular organ; forward-tilted over bladder
Spatial relations
- Anterior to rectum, posterior to urinary bladder
Layered wall structure
1. Perimetrium — outer serous layer (visceral peritoneum)
2. Myometrium — thick smooth-muscle middle layer
- Expands dramatically during pregnancy
- Contracts forcefully during labor to expel fetus
1. Endometrium — highly vascular inner mucosal layer
- Site of implantation & embryonic/fetal development
- Superficial functional layer shed monthly as menses if no implantation
Anatomical regions
- Fundus (dome-shaped superior portion)
- Height measured clinically (pubic bone ➔ fundus) for fetal growth assessment
- Body (main central portion)
- Receives and houses implanted embryo
- Cervix (inferior constricted segment projecting into vaginal canal)
- Pre-ovulation: swells, secretes watery mucus ➔ facilitates sperm entry
- During pregnancy: forms thick mucus plug ➔ blocks pathogens & protects fetus

Structure: elastic, fibromuscular tube extending cervix ➔ external orifice
Multi-functional
1. Receives penis & semen during intercourse (sperm entry)
2. Serves as exit for menstrual fluid during menses
3. Forms birth canal, allowing passage of fetus
Wall composition
1. Inner mucosal layer
- Arranged in rugae (folds) to permit distension
1. Middle muscular layer
- Smooth muscle enabling expansion & contractions
1. Outer adventitia
- Dense connective tissue with abundant elastic fibers, blood vessels, lymphatics, nerves
- Provides strength + stretch for childbirth

Entire system coordinates endocrine (hormonal), muscular, & structural changes to accomplish reproduction
Ovarian cycle (egg maturation & hormone secretion) is synchronized with uterine cycle (endometrial growth & shedding)
Future lectures will extend these basics into detailed fetal development, hormonal regulation, and clinical correlations (e.g., pregnancy diagnostics, contraceptive mechanisms)