Session 2 - Female reproductive anatomy and Development of tracts Flashcards
What surrounds the ovaries?
A layer of peritoneum, fully enclosing the ovaries.
Why do some women get a sharp pain at ovulation?
During ovulation, oocyte must breach the surface of the ovary, rupturing the follicle.
- In rupturing the follicle breaches the peritoneum (parietal).
- This causes sharp pain, as parietal peritoneum is somatically innervated.
Why do nuns have a tendency to get ovarian cancer?
- Celibacy
- No pregnancy
- Means they will have the maximum number of ovulations possible, causing more trauma to ovarian capsule.
What is an ovarian cyst?
- Fluid filled cyst associated with ovary.
- Can be benign or malignant.
Often go unnoticed.
What would symptoms of a large ovarian cyst be?
- Pain: direct pressure, stretch of peritoneum.
- Torsion: extremely painful.
- Bloating.
Why is it important not to rupture an ovarian cyst when operating?
In case the cyst is malignant.
The rupture could cause cancer cells to disseminate, causing metastases.
What is the outer opening to the cervix called?
The external os.
What is the difference between the external os in different women?
Not had child = small circular os.
Had child = slit like os (wider)
Why may the inner part (of cerical canal) be visualised during speculum? What is this called?
- Transitional zone
- Between external os and internal epithelium of cervix.
(can be due to oestrogen pill) os unfurls a bit.
How would a cervical cancer appear?
Redness on os, due to blood vessels.
Unfurled os.
What happens to the contents of the abdomen during late pregnancy?
What are some symptoms?
Pushes on stomach, diaphragm, colon and bladder.
Can cause reflux, constipation, frequent urination etc.
- Round ligament stretches (on uterus) can be painful.
What is the most common site for ectopic pregnancy?
The ampulla of the uterine tube.
Why can ectopic pregnancies occur in many different parts of the body?
Due to the oocyte rupturing into the peritoneum briefly before moving into fimbriae.
Could potentially move anywhere within the peritoneal cavity (but rare)
What is an important factor when a female of reproductive age presents with abdominal pain?
PREGNANCY TEST!
Could be ruptured ectopic, which if not discovered can cause internal bleeding and death quickly!
Which two main types of cell are present in the uterine tubes? What do they do?
- Ciliated cells: waft egg toward uterus.
- Peg cells (secretory): secrete factors which maintain the egg.
What is special about the female peritoneal cavity?
There is a communication between the peritoneum and the outside word (at the uterine tubes)
- Air could very possibly enter the the peritoneum, blowing into vagina etc
What is the relationship between the uterus/ female reproductive system and the peritoneum?
Covered in parietal peritoneum, not within the peritoneum. Below it (no term for it)
Which structure does the uterine artery pass through before reaching the uterus?
Broad ligament.
Runs in the double fold of peritoneum.
What is the vesico-uterine pouch?
The pouch formed by peritoneum between the bladder and the anterior of the uterus.
What is the recto-uterine pouch (pouch of douglas).
The pouch formed by peritoneum between the posterior uterus and the rectum.
Which three parts make up the broad ligament?
- Mesovarium - peritoneum covering the overy.
- Mesosalpinx - double folded peritoneum hanging down from uterine tube, to ligament of ovary.
- Mesometrium - forms majority of broad ligament, inferior to the overies and ligament of ovary. (ureter goes through here)
Where does the uterus get its blood supply from?
Branch of the internal iliac artery.
The uterine artery goes over the ureter.
(original water under the bridge)
Why is the anastomosis between the uterine and ovarian arteries important?
Need to be properly clipped in hysterectomy, otherwise profuse bleeding could occur.
What is the normal position of the uterus?
Anteverted and Anteflexed - sits over the bladder.
see diagrams for different positions
Why may a uterus not be anteverted and anteflexed?
Due to genetic factors - can be normal
Due to child-birth etc.
What sort of epithelium lines the uterus?
Stratified squamous epithelium.
Why does the uterus contain lots of glycogen?
- Main food for lacto-bacilli
- Turn it into lactic acid, which helps maintain the acidic pH of the uterus.
Why is it important not to use a douche to clean the vagina?
Can cause serious imbalances of the normal flora in the vagina.
This can cause candidiasis/ thrush.
Should just use water.
What is the vulva?
The external part of the femal genitals (outer part)
What are the labia majora?
The large lips of the vulva, which enclose everything during normal function of the vagina.
What are the labia minora?
Internal lips of vagina, normally enclose in labia majora in normal function.
What is the function of the labia?
They protect the internal structures of the vagina.
What is the vestibule of the vulva?
The part of the vulva between the two labia minora, containing the entrance to the vagina, and the external urethral orifice.
What is the fourchette? Why is it important?
The tense skin at the bottom of the vulva.
Can tear in pregnancy!
What is an episiotomy?
An incision in the perineum and posterior vagina.
This is to prevent a tear, and damage to the anal sphincter/ rectum.
The cut is repaired by suture.
What are the three types of genital mutilation?
- Clitoridectomy - removal of clitoris.
- Removal of labia majora, minora, and clitoris.
- Everything is removed, sewn up, leaving only a hole for urine.
What are the three main germ layers in embryonic development?
Ectoderm, Mesoderm and Endoderm
Which part of the developing germ disc will form the reproductive system?
The intermediate mesoderm.
What is the cloaca?
The blind ending of at the caudal end of the embryo, where the hindgut, and genito-urinary system initially all meet. (has no mesoderm).
In basic terms, how is the reproductive system made?
- XX or XY
- An indifferent gonad forms.
- Indifferent duct system forms (mesonephric and paramesonephric ducts)
- If testis present: Epididymis + Vas deferens form
- If testis not present: Uterus, tubes + part of vagina form.
What is the uro-genital ridge?
Region of intermediate mesoderm giving rise to both embryonic kidney, and gonad.
Which structures is the indifferent gonad derived from?
- Intermediate mesoderm
- and primordial germ cells
What are the primordial germ cells?
Special population of Pluripotent stem cells, derived from the yolk sac, and migrate into the retroperitoneum (along dorsal mesentery)
Which gene is responsible for driving male development in the primordial germ cells?
Y chromosome carries SRY gene.
- Gonad - testis
- Testicular hormones
- Male duct system
How do the duct systems develop in the embryo before differentiation?
Both Mesonephric (wolffian) and Paramesonephric (mullerian) ducts form. Both end at the urogenital sinus in the cloaca.
What is the mesonephric duct?
Duct which carries urine for the mesonephros (embryonic kidney), which becomes no longer required.
How does differentiation of the internal genitalia occur in males?
- Functional testis present
thus:
1) Testis produces Mullerian inhibiting hormone, which suppresses mullerian (paramesonephric) duct development.
2) Testis produces androgens (testosterone) which supports wolffian (mesonephric) duct development.
How does differentiation of the duct system occur in a female embryo?
- No tesits present.
thus. .. - No mullerian inhibiting hormone, so no suppression of mullerian duct development.
- No testis producing androgen, so wolffian duct degenerates.
What is Androgen insensitivity syndrome?
(In a MALE)
The receptors for testosterone do not work.
thus
- Wolffian ducts do not survive
- But Mullerian inhibiting hormone is still present (testis), so Mullerian ducts degenerate.
(No duct system at all)
What happens in development of a female embryo with exogenous androgen present?
Female (no testis)
- exogenous androgen will support the wolffian duct.
- No mullerian inhibiting hormone, so mullerian ducts will develop too.
Has BOTH wolffian and mullerian duct systems.
What happens to the mesonephric duct in males, under androgen stimulation?
Converted to vas deferens and epididymis.
Migrates with testis as it descends.
How do the paramesonephric ducts develop into the female internal genitalia?
- Appear as invaginations of epithelium of urogenital ridge.
- Caudally: Make contact with cloaca
- Cranially: Open into abdominal cavity
The two ducts aim towards each other, and fuse, to form one tube, the Uterus
(diagrams)
Which structures form part of the vagina?
- Endoderm tissue from urogenital sinus forms distal vagina, and hymen.
- Paramesonephric duct forms proximal vagina (just before cervix) and uterus.
What are the basic components of the indifferent External genitalia?
Genital tubercle
Genital folds
Genital swellings
How do external genitalia differentiate in male?
The genital tubercle elongates to and the genital folds fuse, to form the spongy urethra.
The genital tubercle develops into the glans.
Influenced by dihydrotestosterone.
How do the indifferent external genitalia develop in females?
No fusion occurs in females.
Labia minora and majora develop.
The genital tubercle forms the clitoris.
The urethra opens into the vestibule.
What happens to the testis in the embryo as the male develops?
Testis descend, pulled by gubernaculum, through the inguinal canal, becoming external (taking the layers with them) Processus vaginalis (covering of peritoneum) Becomes tunica vaginalis (separates)
What happens to the primordial germ cells and the indifferent gonad in the male and female?
Male - Development of seminiferous epithelium, containing primordial germ cells in medulla.
Female - No medulla development, outer cortex becomes studded with primordial germ cells (primordial follicles)
How do the ovaries end up in their final position?
- Gubernaculum attaches inferiorly to labio-scrotal folds.
- Ovaries descend to pelvis.
- Uterus has developed, which blocks/ prevents further descent!
What is the round ligament remnants of?
Remnants of the gubernaculum, goes into inguinal canal and labia (followed by lymphatics).
