1 THE FEMALE REPRODUCTIVE SYSTEM Lois E Brenneman, MSN, ANP, FNP, C

13 Pages·2001·0.86 MB·English

THE FEMALE REPRODUCTIVESYSTEM
Lois E Brenneman, MSN, ANP, FNP, C
OVERVIEW
- Female
- Urinary and reproductive system are completely separate
- Internal structures located in lower pelvis; inside bony pelvis; behind pubic bone
- Male: combine urinary and reproductive system in the male
EMBRYOLOGY
- Gonads in both sexes are bipotential until 6th week of gestation
- Embryonic gonads may be become either testes or ovaries
- Male/female development begins at 7th week
- Locus on Y-chromosome determines testicular development
- Causes development into testes
- Caused testicular-determiningfactor
- Genetically female embryo: gonad develops into ovary
- Ovary-determining genes theorized; have yet to be identified
- Cortex of gonad accumulates cells that develop into ovarian follicles
- Each follicle contains primary oocyte
- External genitalia bipotential until 8th week of gestation
- Genetic male embryo: dihydrotestosterone effects differentiation into male genitalia
- Binds to androgen receptors in external genitalia
- Dihydrotestosterone is metabolite of testosterone
- Without dihydrotestosterone: genitalia develop into female structure
- Will develop into female genitalia regardless of genotype (XX or XY)
-Testicular feminization syndrome
Genetic male (XY) which develops female genitalia due to inherited
absence of testosterone receptors
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EXTERNAL REPRODUCTIVE STRUCTURES
Mons pubis: rounded skin-covered fat pad - anterior to symphysis pubis
- Darker, coarser hair forming inverted triangle (base situated over mons)
- Abundance of sebaceous glands
Labia majora (singular: labium majus)
- Analogous to male scrotum; forms two lips
- Outermost structures of vulva extend from mons pubis to anus
- Folds of skin and fat
- After puberty deeper pigmentation and covered with coarse hair
- Normally close over urethral opening and vaginal introitus
Labia minora (singular: labium minus)
- Situated between labia majora
- Delicate cutaneous structure; smaller than labia majora
- Skin, fat and some erectile tissue; usually hairless and pink
- Extend at hood of clitoris to base of vagina
- Sebaceous glands with odor-bearing secretions
- Outline the vestibule (see below)
Clitoris
- Located below clitoral hood (prepuce) - joining of labia minora
- Erectile organ - analogous to male penis
- Engorges during sexual stimulation
- Approximately 2 cm x 0.5 cm
- Very vascular with extensive innervation
Urethra - urinary meatus
- External opening of internal urinary bladder
- Posterior to clitoris
- Lies within vestibule (see below)
- Location of Skene’s Glands (see below)
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Vestibule - almond shaped between lines of attachment of labia minora
-Clitoris situated at superior angle
-Fourchette is the inferior boundary
- Dimensions: 4-5 cm long; 2 cm wide when labia separated
- Covered with pink membranes; delicate stratified epithelium
- Major structures opening into the vestibule
- Urethral opening (anteriorly)
-Vaginal opening (midportion)
-Bartholin’s glands - 2 lateral secretory ducts (lubricating)
Bean-shaped, mucus-secreting glands on either side of vaginal orifice
Secretions increase during sexual excitement
Frequent site of gonorrheal infection
-Skene’s glands: tiny mucus secreting glands
- Situated inside and just posterior to external urethral meatus
- Lubricating functions
- Acts in concert with urethral glands to keep meatus lubricated
Introitus
- Opening between the external and internal genitalia
-Hymen: connective tissue membrane surrounds introitus
- Determines size and shape of introitus
- Normallyruptured during initial intercourse or other trauma
- Intact hymen does not confirm virginity
- Can stretch without tearing
- Configuration may be circular, oval or sieve-like
- Occasionally imperforate - occludes menstrual flow
Perineal body - lies between fourchette and anus
- Fibrous connective tissue - site of episiotomy
- Insertion site of several peritoneal muscles
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INTERNAL REPRODUCTIVE STRUCTURES LOCATED IN LOWER PELVIS
Ovaries - female gonads
STRUCTURE
- Paired glandular organs; pinkish-white to gray
- Size: 3-5 cm long; 1.5-3 cm wide
- Situated in lateral pelvic wall on either side of uterus
- Suspended in round ligament; not directly attached to oviducts
-Fallopiantubes not directly connected to ovary (open to peritoneal cavity)
- Abnormal implantation outside reproductive system can occur (rare)
- Egg can transport from opposite tube
- Layers of ovary
- Medulla(inner layer): blood vessels, lymphatics, connective and nerve tissue
- Cortex: (outer layer)
FUNCTION
Female gamete production
- Birth: 400,000 primordial egg cells per
ovary
- Adolescence: 30,000 to 50,000 remain
- No additional egg cells produced after
birth (in contrast to male: sperm)
Function is regulated by anterior pituitary
Follicles:
- Oocytes in sustained meiotic phase - surrounded by granulosa cells
- Mature into ovum over next 30 years or disintegrate
Ovulation: ovaries produce ovum in response to hormonal stimulation
Fallopian tubes(oviducts) - functions totransport ovum and sperm
Extend outward from each side of body of uterus
Conduit between ovary and uterus
- Facilitates transport of fertilized ovum
- Passageway for drainage of tubal secretions
Attach at upper uterus - 13 cm in length; 0.5-1.0 cm in width
Narrow muscular tubes - lines with cilia
Two (2) Layers; surrounded by layers of involuntary muscle (muscularis layer)
- Inner
- Outer serous layer: smooth layer (serosa) - part of visceral peritoneum
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Structural sections of fallopian tubes
Interstitial sections: lies within uterine wall
Isthmususual site for tubal ligation
Narrowest section; closest to uterus
Opens into uterine cavity
Thick muscular wall with narrow lumen
Ampulla - thin walled - usual site of fertilization
Longest and widest section - 2/3 of total
length
Widens progressively to wide distal opening (infundibulum)
Thin walled, highly folded lining
Infundibulum: fimbriated end; lies in close proximity to ovary
Fimbriae: finger-like projections
PHYSIOLOGY
Cilia:hair-like projections which facilitate transport of fertilized ovum
Muscularis layer: muscle contraction
Fimbriae: bend closer to ovary during the peri-ovulation period
Uterus: thick-walled muscular organ - pear-shaped
Located between bladder and rectum
Structure
Fundus: portion above insertion of fallopian tubes
Cervix: lower constricted portion (protrudes into vagina)
Body of uterus: between fundus and cervix
Uterine walls - tri-layered
-Endometrium: inner layer of cavity
- Continuous with lining of fallopian tubes and vagina
- Superficial layer: sheds during menstruation
-Basal layer: cells regenerate superficial layer between cycles
-Ciliated cells: moves secretions out of cavity into vagina
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-Myometrium: middle, muscle layer
- Major portion of uterine wall
- Continuous with myometrium of fallopian tubes and vagina
- Extends into all supporting ligaments except broad ligament
- Muscle contractions: menstrual fluid or products of conception
-Dysmenorrhea: painful contractions during menses
-Labor: severely painful obstetrical contractions
- Expands over 4000 times during pregnancy/labor
-Perimetrium: external peritoneal covering -serous
- Outer serous covering; derived from abdominal peritoneum
- Outer layer merges with peritoneum covering broad ligaments
- Reflected over bladder wall anteriorly - vesicouterine pouch
- Posteriorly extends to form cul-de-sac or pouch of Douglas
Proximity to bladder results in urinary symptoms esp during pregnancy or with uterine
infections
Ligamentous support: four sets
-Broad ligaments: run laterally from body of uterus to pelvic side walls
- Support vagina - prevent prolapse
-Round ligaments: from fundus laterally (below tubes) into each labium majus
- Holds fundus forward.
-Uterosacral ligaments: uterocervical junction to sacrum (supports cervix)
- Uterovesical ligament (fold of peritoneum: over fundus to bladder)
- Rectovesical ligament: fold of peritoneum: posterior surface of uterus
and reflected on rectum
-Cardinal: transverse cervical ligaments
- Firmly joined to supravaginal area of cervix
Impairment of ligaments (senility, childbirth trauma) results in various anomalies
Uterine prolapse and other anatomic distortion
Cystocele, rectocele
Anatomic orientation of uterus within pelvis is variable
Anteverted (most common)
Antiflexed
Retroverted
Retroflexed
Will present differently on bimanual exam esp with fundal palpation
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Cervix: lower portion of the uterus
Round cervix: neck of uterus - protrudes into vagina
Firm structure which becomes soft and pliable during hormones of pregnancy
Small, shiny and pink; firmer than corpus (connective tissue)
Structure: connective tissue matrix of glands and muscle tissue
Glands secrete mucus:consistency/quantity varies with menstrual cycle and pregnancy
Nabothian cyst: obstructed ducts causing cysts on cervix
Mucus changes in response to hormonal variations
Vascular supply from uterine artery: can cause significant obstetrical blood loss
Endocervix: lining of cervical canal (endocervical canal)
Ectocervix: cervical portion extending outward from the external cervical os
Cervical os:opening of cervix forming pathway between vagina and uterus
External os: vaginal opening
Uterine os: uterine opening
Endocervical canal: space between two openings - 2 to 2.5 cm
- Line by columnar epithelium
- Sampled during routine pap smear
- Columnar epithelium secretions form mucus plug after conception
- Portal for menstrual discharge and insemination
Os varies with parity and stage of life
Nulliparity: round os
Parous: slit-like, irregular
Menopausal: small, tight (sometimes stenotic)
Epithelium 2 types: squamous epithelium and columnar epithelium
Squamous epithelium: smooth shiny and pink - four layers
Basal layer: lies within basement membrane, 1-2 cell layers
Parabasal layer: 3-4 cell layers
Intermediate layer: thicker than basal or parabasal
Superficial layer: mature cells; continuously shed; thickest layer
Columnar epithelium
Dark red and granular; secretes mucus
Lines endocervix
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Squamocolumnar junction - SCJ
- Boundary between squamous and columnar epithilium
- Boundary migrates over time - change due to squamous metaplasia
Adolescents: junction visible on external cervix
Involutes into canal over time
Menopause: extends up canal with decreasing estrogen levels
-Eversion, ectropion, ectomy: where visible on ectocervix
Granular, red - function of columnar epithelial component
Well-circumscribed area (cervical ectopy)
Sometimes erroneously called “erosion”
Transformation zone - results from squamous metaplasia
Critical to sample this zone during collecting pap
Region is particularly susceptible to dysplasia
Squamous metaplasia:transformation of columnar epithelium into squamous
epithelium
- Occurs as columnar changed to squamousepithelium
- Change occurs naturally over time in response to increasing estrogen levels
- SCJ found on the ectocervix in adolescents or young nulliparous
- Increasing estrogen levels (acid environment ) cause metaplasia with
maturity
- SCJ found at os or further inside canal on mature women esp s/p
childbirth
- SCJ can be high in endocervical canal on menopausal women
- Area of metaplasia called endocervical cells
- Critical to sample this area during routine paps
- Metaplastic region most susceptible to neoplasia
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Vagina:fibromuscular tube connecting internal and external organs
- Approximately 9 cm long; normally pinkish-red
- Free of sensory nerve fibers
- Located behind urinary bladder and urethra; anterior to rectum
- Cervix protrudes into upper end
-Fornices: recesses formed by protrusion of cervix
- Anterior fornix, posterior fornix
- Thin-walled allows for palpation of ovaries and uterus during bimanual exam
- May pool semen after ejaculation facilitating intermittent release into os
- Functions
- Discharge route for menses and other secretions
- Organ of sexual reproduction - receptacle for penis during intercourse
- Birth canal with dilated cervix to expel fetus
- Conduit for sperm to travel toward ovum
- Structure - lined with squamous epithelium from cervix to vestibule
- Two longitudinal folds
- Transverse folds - rugae
- Normally moist;very distensible: stretch/contract with intercourse or delivery
- No mucus secreting glands: lubricated by cervical and glandular secretions
- Normal physiology
- pH 3.8 to 4.2 - bacteriostatic
- Responsive to ovarian hormone levels
- Colonized by lactobacilli (Doderlein’s bacilli) - normal vaginal flora
-Bacterial vaginosis results when normal flora are disrupted
EFFECTS OF ESTROGEN STIMULATION
- Proliferation and maturation of mucosa
- Thickened mucosa and increased epithelial glycogen
- Glycogen fermented to lactic acid by lactobacilli resulting in acid pH
- Menopausal ovarian failure results in changes from low estrogen levels
- Urogenital atrophy
- Thinning, flattening and friability of vulva
- Loss of vaginal rugae, shortening of canal - atrophic vaginitis
-Dyspareunia - atrophic vaginitis
-Maturation Index: estimation of estrogen level
- Examination of cellular structure and configuration of epithelium
- Cytological exam of vaginal scrapings
- Determines rate ratio of cell types
- Parabasal (least mature)
- Intermediate
- Superficial (most mature)
-Index varies with stage of life
0-40-60 during reproductive years
30-40-30 with perimenopause
- Decreasing estrogen levels
- Shift to left
75-20-0 during postmenopausal period
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VAGINAL ECOLOGY
- Minimal innervation: symptoms of infection evident only when discharge irritates vulva
-Estrogenized epithelium well supplied with glycogen (within epithelial cells)
Glycogen-rich epithelial cells rises with menarche
Menopause results in declining levels of estrogen and associated glycogen
- Normal flora - lactobacilli - metabolize glycogen
- Pleomorphic, gram-positive aerobic or facultative anaerobic
- Dominate normal flora - 96% in healthy woman
- Slightly mobile straight rods with variable length
-Maintain acid pH (3.8-4.2) of vaginal discharge via producing lactic acid
- Acid environment and released peroxide inhibits pathogenic anaerobes
- Acid pH inhibits bacterial adherence to epithelial cells
- Most vaginal organisms exist symbiotically within the acid environment
-Bacterial vaginosis results when normal flora balance is upset
- Results from factors which decrease lactobacilli thus decrease acidity
- Overgrowth of pathogens normally present in small amounts
- Progesterone results in shedding of glycogen-rich cells into vaginal pool
MENSTRUAL CYCLE
Cyclical bleeding with shedding of endometrial lining during reproductive years
Menarche: first menstrual bleed
Menopause: last menstrual bleed
Anovulatory cycles: bleeding without antecedent ovulation - often results in DUB *
Cycle induces changes in other organs: breasts, uterus, skin, ovaries, sometimes affect
* Dysfunctional uterine bleeding
HORMONAL CONTROL
Hypothalamic-Pituitary Hormones
GnRH from hypothalamus stimulates
anterior pituitary
Anterior pituitary gland secretes
FSH and LH (also secretes prolactin
stimulates lactation)
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