1 Reproductive Tract Structure and Function Patricia W. Caudle Relevant Terms Adrenarche—initiation of increased adrenal androgens Labia minora—folds of tissue between the labia majora Ampulla—wider end of the fallopian tube Lactobacilli—normal bacterial flora of the vagina Atresia—degeneration and absorption of immature follicles Leptin—hormone secreted by fat cells that plays a key role Bartholin glands—pea sized bilateral vulvar glands that in appetite and metabolism secrete fluid to lubricate the vagina Meatus—opening of the urethra Cervix—lower portion of the uterus Menarche—initiation of menses Chadwick’s sign—bluish color to the cervix, vagina and labia Metaplasia—normal replacement of one cell type with another due to increased blood flow in pregnancy, can be seen as Mittelschmerz—pain upon ovulation early as 6‐8 weeks gestation Myometrium—middle, muscular layer of the uterus Clitoris—erogenous organ with erectile tissue covered by Mucin—glycosylated proteins that form mucus that acts as labia minora lubricant and protectant Cornua—both sides of the upper outer area of the uterus Nulliparous—a woman who has never had a child where the fallopian tubes join the uterus Oogenesis—transformation of oogonia into oocytes Ectropion—visible columnar cells at the cervical os Oogonia—primordial female germ cells Endocervical canal—passageway within the cervix to the Os—opening of the cervix inner uterus Parous—woman who has had a child Endometrium—lining of the uterus Peritoneum—thin membrane around abdominal organs that Escutcheon—pubic hair covers the bladder, uterus, and rectum Fimbriae—fingerlike projections that move the egg toward Rectouterine pouch—fold of peritoneum between the uterus and into the fallopian tube and the rectum First polar body—other half of the product of division of the Rectovaginal septum—tissue between the rectum and vagina primary oocyte Rugae—thin ridges of tissue like an accordion that allow for Fornix (fornices)—spaces around the cervix in the vagina expansion in the vagina Fourchette—area immediately below the introitus Squamocolumnar junction (SCJ)—where squamous cells and Gonadarche—period when ovaries begin to secrete sex hormones columnar cells meet on the cervix Gonadostat—gonadotropin‐releasing hormone pulse generator Skene glands—small bilateral vulvar glands that secrete fluid Granulosa cells—cells lining an ovarian follicle that become to lubricate the urethra luteal cells after ovulation Thelarche—breast development Ground substance—mucopolysaccharideCOPYRIGHTED between smooth Vasovagal MATERIAL response—bradycardia and syncope caused by muscle and collagen of the cervix stretching the cervical canal Hart’s line—line of change where skin transitions to smoother, Vesicouterine pouch—fold of peritoneum between the moist skin bladder and the uterus Hegar’s sign—softening and compressibility of the uterine isthmus Vesicovaginal septum—tissue between the bladder and the Hymen—membranous ring of tissue at the introitus vagina Introitus—opening to the vagina Vestibule—area inside the labia minora where openings of the Isthmus—uterine “neck” between cervix and body urethra and the vagina are found Labia majora—two rounded folds of adipose tissue covered Zona pellucida—membrane surrounding the plasma with pubic hair ­membrane of the oocyte Prenatal and Postnatal Care: A Woman-Centered Approach, Second Edition. Edited by Robin G. Jordan, Cindy L. Farley and Karen Trister Grace. © 2019 John Wiley & Sons, Inc. Published 2019 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/jordan/prenatal 5 0003408923.INDD 5 3/10/2018 10:21:37 AM 6 Reproductive Tract Structure and Function Anatomy of the Female Reproductive System the mons to the perineum on either side of the vaginal ­opening. The labia minora, found between the majora, An understanding of the anatomy of the female repro- are thinner, pinkish in color, and hairless (Bickley & ductive system is essential in caring for women. It is Szilagyi, 2013). The labia majora have the same position important to be able to recognize normal structures and and general structure as the male scrotum and arise from to appreciate that there is a wide variation of normal the same tissues during embryonic development. among women. The labia minora have two folds above where they divide to descend on either side of the vestibule, ending External Genitalia at the fourchette just below the introitus, or the opening The vulva is a term designated for the external genitalia to the vagina. The upper fold forms the prepuce over the of the female. The vulva includes the mons pubis, labia clitoris and the lower fold is the frenulum of the clitoris. majora and minora, clitoris, vestibule, hymen, urinary The clitoris is an erogenous organ with erectile tissue. meatus, and Skene and Bartholin glands. Figure 1.1 The clitoris is exquisitely sensitive in most women and is and Figure 1.2 illustrate the external genitalia and its the primary source of sexual pleasure. ­development from embryonic structures. The vestibule is that area inside the labia minora The mons pubis is the cushion‐like area over the pubic where the openings to the urethra, vagina, and Skene bone. In adult woman, the mons is covered with curly, and Bartholin gland ducts are found. The urethra is just coarse pubic hair called the escutcheon. The pubic hair above the vaginal opening and below the pubic arch. The distribution is usually triangular but may extend up vaginal introitus is rimmed with the hymen or its tags. toward the umbilicus in a diamond shape in women who Bartholin glands are located at either side of the lower have higher levels of serum androgens. portion of the introitus. The ducts for these glands open The labia majora consist of two rounded folds of near the hymenal ring at 5 o’clock and 7 o’clock. Skene ­adipose tissue covered with pubic hair that extend from glands and ducts are found near the urethral meatus. The vulva refers to the external genitals of the female. Mons pubis Prepuce of clitoris Labia majora (spread) Clitoris Labia minora (spread External urethral orifice exposing vestibule) Vaginal orifice (dilated) Hymen Anus Inferior view Figure 1.1. External female genitalia. From Tortora & Derrickson (2017). Used with permission. 0003408923.INDD 6 3/10/2018 10:21:38 AM Physiological Foundations of Prenatal and Postnatal Care 7 The external genitals of male and female embryos remain undifferentiated until about the eighth week. Genital tubercle Urethral folds Urethral groove Labioscrotal swelling Urogenital sinus Perineum Anus Undifferentiated stage (about 5-week embryo) Glans penis Clitoris Urethral folds Labioscrotal swelling Perineum Anus 10-week embryo External urethral orifice Glans penis Clitoris Penis Labia majora External Labia minora urethral orifice Vaginal orifice Scrotum Vestibule Anus Near birth Male development Female development Figure 1.2. Development of external genitalia from embryonic structures. From Tortora & Derrickson (2017). Used with permission. Hart’s line is the line of change in the vestibule where genitalia examination. Underlying these structures are vulvar skin transitions to smoother, moister skin around the superficial muscles of the perineum and anal sphinc- the urethral meatus and the introitus. ter. The superficial muscles most often affected by child- Below the vulva is the perineal body and anal opening. birth include the bulbocavernosus muscle, the superficial These structures are examined as part of the external transverse perineal muscle, and the external and internal 0003408923.INDD 7 3/10/2018 10:21:38 AM 8 Reproductive Tract Structure and Function The perineum is a diamond-shaped area that includes the urogenital triangle and the anal triangle. Pubic symphysis Clitoris Bulb of the vestibule External urethral orifice Vaginal orifice (dilated) Ischiocavernosus muscle Bulbospongiosus muscle Greater vestibular (Bartholin’s) gland Urogenital triangle Superficial transverse perineal muscle Ischial tuberosity Anal triangle Anus External anal sphincter Gluteus maximus Coccyx Inferior view Figure 1.3. Superficial muscles of the perineum. From Tortora & Derrickson (2017). Used with permission. anal sphincters. These structures, with the exception of pudendal nerve and the inferior hypogastric plexus, the internal anal sphincter, converge on the central ten- both of which derive from sacral nerve (S) 2–4. Lymph don of the perineum found between the introitus and the drainage for the vagina is to the para‐aortic nodes. anus. The central tendon is part of the perineal body that The vagina is lubricated by an epithelial glycoprotein may tear or be cut by episiotomy during birth (Figure 1.3). coat and transudate, cervical mucus from the endocervical columnar epithelium, and fluids from the Bartholin and Internal Genitalia Skene glands (Tufts et al., 2014). The milieu of the vagina is The vagina is a musculomembranous tube that gives access acidic and presents a barrier to many bacteria. The pH is to the cervix for coitus and serves as the birth canal. The normally between 4.0 and 4.5 in women of childbearing lower third of the vagina is supported and fixed by the pub- age and is maintained by the estrogen effect on the epithe- ococcygeus muscles of the levator ani group. The upper lial glycoprotein coat and lactobacilli (normal­ bacterial portion of the vagina and the cervix are supported by flora of the vagina). Vaginal secretions increase during the cardinal and uterosacral ligaments. This portion of the pregnancy due to increased vascularity. vagina is capable of amazing expansion to accommodate The lower portion of the vagina is separated from the birth. Vaginal rugae allow for elasticity and expansion. urinary bladder by the vesicovaginal septum, and is sep- Vaginal length varies with genetics, parity, age, and estro- arated from the rectum by the rectovaginal septum. The gen effect. On average, the length of the vagina is about rectovaginal septum is at risk for lacerations and tears in 6–8 cm anteriorly and 7–10 cm along the posterior wall the event of an operative birth.