Reproductive System Week 5 Flashcards
Describe the ovaries
Almond-shaped and -sized female gonads
In which the oocytes develop
Endocrine glands - produce steroid hormones
What structure suspends the ovary?
The mesovarium - subdivision of the broad ligament of the uterus
How does the structure of the ovary differ between prepubertal and postpubertal women?
Prepubertal - connective tissue capsule (tunica albuginea) comprising surface of the ovary is covered by smooth layer of ovarian mesothelium/surface epithelium - single layer of cuboidal cells - gives surface dull, greyish appearance - contrasts with shiny surface of adjacent peritoneal mesovarium which it is continuous with
Postpubertal - surface epithelium becomes progressively scarred and distorted - due to repeated rupture of ovarian follicles and discharge of oocytes during ovulation - scarring less in women who take oral contraceptives inhibiting ovulation
In what structure do the ovarian vessels, lymphatics and nerves cross the pelvic brim, passing to and from the superolateral aspect of the ovary?
Suspensory ligament of the ovary - becomes continuous with the mesovarium
What structure tethers the ovary to the uterus?
a short ‘ligament of the ovary’
Where are the ovaries usually sitting?
Laterally between the uterus and the lateral pelvic wall
What is the ligament of the ovary a remnant of?
The superior part of the ovarian gubernaculum of the foetus
What structures does the ligament of the ovary connect?
Proximal end of ovary to lateral angle of the uterus just inferior to entrance of uterine tube
What is the mesovarium?
Short peritoneal fold or mesentery - suspends the ovary
What is the broad ligament?
Mesentery of the uterus
What is the consequence of the ovary being intraperitoneal?
Oocyte is expelled at ovulation and passes into peritoneal cavity
But normally trapped by fimbriae of the infundibulum of the uterine tube and carried into the ampulla - may be fertilised here
What is the function of the uterine tubes?
Conduct the oocytes from the peri-ovarian peritoneal cavity to the uterine cavity
Provide the usual site of fertilisation
Where are the uterine tubes?
Extend laterally from the uterine horns and open into the peritoneal cavity near the ovaries
Describe the uterine tubes
Extend laterally from the uterine horns and open into the peritoneal cavity near the ovaries
Approx. 10cm long
Lie in a narrow mesentery - mesosalpinx - form the free anterosuperior edges of the broad ligaments
In the ideal disposition - tubes extend symmetrically posterolaterally to the lateral pelvic walls - arch anterior and superior to the ovaries in the horizontally disposed broad ligament
In reality - tubes commonly asymmetrically arranged - one or the other often lying superior and even posterior to the uterus
Describe the four parts of the uterine tube
Infundibulum - funnel-shaped distal end of the tube - opens into peritoneal cavity through abdominal ostium - finger-like processses (fimbriae) spread over medial surface of the ovary - one large fimbria is attached to the superior pole of the ovary
Ampulla - widest and longest part of the tube - begins at medial end of infundibulum - fertilisation usually occurs here
Isthmus - thick-walled part of the tube - enters the uterine horn
Uterine part - short intramural segment of the tube - passes through uterine wall - opens via uterine ostium into uterine cavity at uterine horn
Describe the arterial supply of the ovaries and uterine tubes
Ovarian arteries arise from abdominal aorta - descend along posterior abdominal wall - cross over external iliac vessels at pelvic brim - enter suspensory ligaments - approach lateral aspects of ovaries and uterine tubes - terminates by bifurcating into ovarian and tubal branches - anastomoses with ovarian and tubal branches of uterine arteries - collateral circulation from abdominal and pelvic sources to both structures
Ascending branches of uterine arteries - branches of internal iliac arteries - course along lateral aspects of uterus to approach medial aspects of ovaries and tubes - terminate by bifurcating into ovarian and tubal branches - anastomoses with ovarian and tubal branches of ovarian arteries
Describe the venous drainage of ovaries and uterine tubes
Veins draining ovary form pampiniform plexus of veins in broad ligament near ovary and uterine tube
Usually merge to form singular ovarian vein –> leaves lesser pelvis with ovarian artery
Right ovarian vein ascends to enter IVC
Left ovarian vein drains into left renal vein
Tubal veins drain into ovarian veins and uterine venous plexus
Describe the innervation of the ovaries and uterine tubes
Derives partly from ovarian plexus (descending with ovarian vessels) and partly from uterine (pelvic) plexus
Superior to pelvic pain line because intraperitoneal –> visceral afferent pain fibres ascend retrogradely with the descending sympathetic fibres of the ovarian plexus and lumbar splanchnic nerves to cell bodies in T11-L1 spinal sensory ganglia
Visceral afferent reflex fibres follow parasympathetic fibres retrogradely through the uterine (pelvic) and inferior hypogastric plexuses and the pelvic splanchnic nerves to cell bodies in S2-4 spinal sensory ganglia
Describe the uterus
Thick-walled, pear-shaped, hollow muscular organ
Embryo and foetus develop in uterus
Muscular walls adapt to the growth of the foetus and then provide the power for its expulsion during childbirth
Non-gravity uterus usually lies in lesser pelvis - body lying on urinary bladder and its cervix between the urinary bladder and rectum
Very dynamic structure - size and proportions of which change during various changes of life
Describe the position of the uterus
Usually anterverted (tipped anterosuperiorly relative to axis of vagina) and anteflexed (flexed or bent anteriorly relative to the cervix- creating angle of flexion) - so that its mass lies over the bladder When the bladder is empty the uterus typically lies in a nearly transverse plane Position of the uterus changes with degree of fullness of bladder and rectum, and stage of pregnancy
Describe the size of the uterus
Size varies considerably
Non-gravid uterus is approximately 7.5cm long, 5cm wide and 2cm thick
Weighs approx 90g
Describe the two parts of the uterus
Body of the uterus - forms superior 2/3s - lies between layers of the broad ligament and is freely movable - 2 surfaces (vesical and intestinal)
- demarcated from cervix by the isthmus- relatively constricted segment - approx 1cm long
- fundus - rounded part - lies superior to uterine Ostia
Cervix of the uterus - cylindrical, relatively narrow inferior 1/3 of the uterus - approx 2.5cm long in an adult non-pregnant woman:
- supravaginal - between isthmus and vagina - separated from bladder anteriorly by loose connective tissue - from rectum posteriorly by recto-uterine pouch
- vaginal - protrudes into sueriormost anterior vaginal wall - rounded - surrounds external os of the uterus - surrounded by vaginal fornix
How long is the uterine cavity?
6 cm in length from external os to wall of the fundus
What are the uterine horns?
Superolateral regions of the uterine cavity where the uterine tubes enter
What does the uterine cavity continue inferiorly as?
Cervical canal - fusiform canal - extends between anatomical internal os to the external os
What constitutes the birth canal?
Uterine cavity (in particular cervical canal) Lumen of the vagina
What is the birth canal?
What the foetus passes through at the end of gestation
Describe the three layers of the uterine wall
Perimetrium - serous coat - peritoneum supported by thin layer of connective tissue
Myometrium - middle coat of smooth muscle - greatly distended (more extensive but thinner) during pregnancy - main branches of blood vessels and nerves of uterus - contractions during childbirth are hormonally stimulated at intervals of decreasing length to dilate the cervical os and expel the foetus and placenta - during menses contractions may produce cramping
Endometrium - Inner mucous coat - firmly adhered to underlying myometrium - actively involved in menstrual cycle - differs in structure with each stage of cycle - if conceptions occurs blastocyst implants into this layer - if conception does not occur the inner surface of this coat is shed during menstruation
Describe the muscular tissue of the cervix compared to the uterus
Amount of muscular tissue is markedly less in cervix - mostly fibrous and is composed mainly of collagen with small amount of smooth muscle and elastin
Describe the ligaments of the uterus
Ligament of ovary attaches to uterus posteroinferior to uterotubal junction - vestige of ovarian gubernaculum
Round ligament of the uterus attaches anteroinferior to the uterotubal junction - vestige of ovarian gubernaculum
Broad ligament of uterus - double layer of peritoneum (mesentery) - extends from ides of the uterus to lateral walls and floor of pelvis - assists in keeping uterus in position - two layers continuous with each other at a free edge that surrounds the uterine tube - laterally the peritoneum is prolonged superiorly over the vessels as the suspensory ligament of the ovary - between layers ligaments of the ovary lie posterosuperiorly and round ligaments of uterus lie anteroinferiorly - uterine tube lies in anterosuperior free border within a small mesentery called the mesovarium on posterior aspect of broad ligament - largest part of the broad ligament is the mesometrium which serves as mesentery for the uterus itself
What provides dynamic support to the uterus?
Pelvic diaphragm - tone during sitting and standing and active contraction during increase itnraabdominal pressure is transmitted through the surrounding pelvic organs and the endopelvic fascia in which they are embedded
What provides passive support to the uterus?
It’s position - anteverted and anteflexed on top of the bladder - intraabdominal pressure increase presses uterus against bladder
- cervix is least mobile part because of attached condensations of endopelvic fascia (ligaments) which may also contain smooth muscle:
- cardinal (transverse cervical) ligaments - thickening of base of broad ligament - extend from supravaginal cervix and lateral parts of the fornix of the vagina to the lateral walls of the pelvis - lateral support -
- uterosacral ligaments - pass superiorly and slightly posteriorly from the sides of the cervix to the middle of the sacrum - opposes anterior pull of round ligament - maintains anteversion - palpable in rectal examination
What is the consequence of dynamic and passive support of the uterus?
Prevents prolapse and disposition of uterus
Which of the female reproductive structures are covered by the peritoneum?
Uterus anteriorly and superiorly except for the cervix
Reflected anteriorly onto the posterior margin of the superior surface of bladder - forms the vesicouterine pouch between the bladder and uterus
and posteriorly over the posterior part of the fornix of the vagina to the rectum - rectouterine pouch
Describe the relations of the uterus
Anteriorly - vesicle-uterine pouch and period surface of the bladder - supravaginal part of cervix is related to the bladder - separated from it by only fibrous connective tissue
Posteriorly- recto-uterine pouch containing loops of small intestine and the anterior surface of the rectum - only the visceral pelvic fascia uniting the rectum and uterus here resists increased intraabdominal pressure
Laterally - peritoneal broad ligament flanking the uterine body and the fascial cardinal ligaments on each side of the cervix and vagina - in the transition between the two ligaments the ureters run anteriorly slightly superior to lateral part of vaginal fornix and inferior to uterine arteries - 2cm lateral to supravaginal part of cervix
Describe the arterial supply and venous drainage of the uterus
Uterine arteries - potential collateral supply from the ovarian arteries
Uterine veins - uterine venous plexus on each side of the cervix - drain into internal iliac veins
Describe the vagina
Distensible musculomembranous tube (7-9cm long)
Extends from middle cervix of the uterus to the vaginal orifice (opening at inferior end)
What structures open into the vestibule of the vagina?
Vaginal orifice, external urethral orifice, ducts of the greater and lesser vestibular glands
What is the vestibule of the vagina?
The cleft between the labia minora
Where does the vaginal part of the cervix lie in the vagina?
Anteriorly in the superior vagina
What are the functions of the vagina?
Canal for menstrual fluid
Forms inferior part of birth canal
Receives penis and ejaculate during sexual intercourse
Communicates superiorly with cervical canal and inferiorly with the vestibule of the vagina
How does the vagina usually sit?
Orifice usually collapsed towards the midline so that its lateral walls are in contact on each side of an anteroposterior slit
Superior to the orifice the anterior and posterior walls are in contact on each side of a transverse potential cavity - H shaped in cross section - except at superior end where cervix holds them apart
Describe the relations of the vagina
Lies posterior to the fundus of the urinary bladder and urethra - projects along the midline of its inferior anterior wall
Lies anterior to anal canal, rectum, and recto-uterine pouch
Lateral to the medial margins of the levator ani (puborectalis muscles), visceral pelvic fascia and ureters
Describe the arterial supply and venous drainage of the vagina
Arteries
Superior vagina - derive from uterine arteries
Middle and inferior vagina - vaginal and internal pudendal arteries
Veins
Vaginal veins form vaginal venous plexuses along the sides of the vagina and within the vaginal mucosa - continuous with the uterine venous plexus as the uterovaginal venous plexus and drain into internal iliac veins through the uterine vein - also communicates with the vesical and rectal venous plexuses
Describe the innervation of the vagina and the uterus
Inferior 1/5 of vagina is somatic - deep perineal nerve - branch of pudendal nerve - only this part is sensitive to touch and temperature - S2-4 nerve roots - somatic afferent and motor
Superior 4/5 of vagina is visceral - uterovaginal nerve plexus - also supplies uterus - travels with uterine artery at junction of the base of the broad ligament and superior part of the transverse cervical ligament - extends to pelvic viscera from inferior hypogastric plexus and the pelvic plexus - pelvic splanchnic nerves - arising from S2-4 - parasympathetic motor fibres to uterus and vagina as well as clitoris and bulb of vestibule - visceral afferent fibres conducting pain from subperitoneal structures (cervix and vagina) - travel with parasympathetic fibres to S2-4 spinal ganglia
Sympathetic innervation - inferior thoracic spinal cord origins - pass through lumbar splanchnic nerves and intermesenteric-hypogastric-pelvic series of plexuses - visceral afferent fibres conducting pain impulses from intraperitoneal uterus - follow sympathetic innervation retrograde to inferior thoracic -superior lumbar spinal ganglia
All visceral afferent fibres from uterus and vagina not concerned with pain follow the parasympathetic route
What is the clinical significance of the two different routes followed by the visceral pain fibres in the female pelvis/pelvic pain line?
Offers mothers variety of types of anaesthesia for childbirth
What is the clinical consequence of the female genital tract communicating with the peritoneal cavity?
Infections of vagina, uterus and tubes (e.g. PID) may result in peritonitis
Inflammation of a tube (salpingitis) may result from infections that spread from the peritoneal cavity
Major cause of infertility - blockage of terrine tubes often as result of salpingitis
How can the patency of the uterine tubes be determined?
Hysterosalpingography - Radio graphic procedure involving injection of a water-soluble radiopaque material or CO2 gas into the uterus and tubes through the external os of the uterus - contrast medium travels through uterus and tubes - accumulation of fluid or appearance of gas bubbles in pararectal fossae region indicates that the tubes are patent
Hysteroscopy - hysteroscoped used - introduced through vagina and uterus
What is ligation of the uterine tubes and when is it used?
Used as surgical method of birth control
Oocytes discharged from the ovaries that enter the tubes degenerate and are soon absorbed
Done by either abdominal tubal ligation (short suprapubic incision made at pubic hair line and involves interruption - often removal of segment of tube and tubal closure by suture ligation) or laparoscopic tubal ligation (fiber optic laparoscope inserted through small incision - usually near umbilicus - apply cautery, rings or clips)
