2 Flashcards
Where do ovaries form?
In the ovarian surface (germinal) epithelium
Why do females sometimes get a sharp pain at ovulation?
- Because it is due to the rupture of the peritoneum when it releases the oocyte
- since the capsule is made of peritoneum
Why do nuns tend to get ovarian cancer?
- every time an oocyte is released, it ruptures the peritoneum making it damage the capsule
- as a result it is susceptible to mitosis and mutations which leads to ovarian cancer
Describe the ovary.
- a paired organ where oogenesis takes place
- has a tunica albuginea
- ovary is full enclosed in parietal peritoneum and contains follicles that will be stimulated by FSH
Describe ovarian cysts and how a patient may present with them.
- increased androgen production may cause cyst formation
- pt. Will experience lots of pain
- cyst may rupture or ovary may twist (torsion)
- will occlude blood supply
- if older women has one, may likely have ovarian cancer
- may cause discomfort during intercourse
Where do ovarian tumours usually arise from?
-commonly from epithelial component or from germ cells in the capsule epithelium
Describe the three parts of the uterus.
- Base/top: fundus
- Body
- Cervix
Describe the suspensory ligament of the ovary.
- allows passage of the ovarian artery and vein to the ovary
- neurovascular pathway bulging into the peritoneum
- ovary is suspended from this ligament as the vessels are coming down from above
- it is a fold of peritoneum
What is the origin of the ovarian artery
-arises from the abdominal aorta
Describe the Fallopian tubes
- allows passage of the ovum to the uterus and is site of fertilization (occurs in ampulla)
- it opens into the peritoneal cavity so it can be very susceptible to infection
- tubes have fimbrae (fingers) to allow a large surface area to “catch” ovum in the peritoneal cavity
- ovum then first reaches the infundibulum (like a funnel for ovary)
- then continues to ampulla
- then ends at isthmus until it reaches fundus of uterus
- lined with cilia which enable transprort of ovum to uterus
- also contains ‘peg’ cells which release substance that supports the egg and sperm
- tube is also very convuluted
What is an ectopic pregnancy? How would you an approach a patient with one?
When the zygote implants in the wrong area such as in the Fallopian tube, isthmus, Fimbria, cornua
-can cause severe haemorrhage
-Ask questions such as:
What is your menstrual cycle like?
Any unprotected sex?
Are you pregnant?
How are your bowel movement?
Any contraception?
-pain would be felt localized around the Fallopian tube
-pain can travel in the paracoelic gutters to the diaphragm, injuring the phrenic nerve
-as a result pain will be felt in the shoulder
-Best investigations would be ultrasound, pelvic exam, blood test for HCG levels
Which part of the uterus expands during pregnancy?
Fundus and it is covered by parietal peritoneum
What are the ligaments around the uterus?
- Round ligament
- ligament of ovary (continuous with the round ligament)
- broad ligament (double fold of peritoneum)
Describe the round ligament
- remnant of the gubernaculum
- goes through the inguinal canal to become the labia major
- helps to keep the uterus antiverted and antiflexed
- stretching this ligament (i.e. pregnancy) can cause pain in the labia
Describe the ligament of the ovary or the ovarian ligament
- continuous with the round ligament
- remnant of gubernaculum
- attaches ovary to uterus
Describe the broad ligament
- is a double fold of peritoneum
- subdivided into 3 parts:
- mesovarium: surrounding the ovary
- mesometrium: between the pelvic wall and the uterus
- mesosalpinx: surrounding the Fallopian tubes
- vessels to the uterus run between the layers of the broad ligament (like mesentry)
- attaches the uterus to the pelvic side walls
Where does the uterine artery originate from?
From internal iliac artery
Describe the anatomical relations in the pelvis and the pouches that are formed
- bladder is anterior to uterus
- rectum is posterior to uterus
- peritoneal reflection between the uterus and bladder anteriorly: vesicouterine pouch
- peritoneal reflection between the rectum and uterus posteriorly: rectouterine pouch (Pouch of Douglas)
- clinically important as they can be a site of fluid collection ex. Haemorrhage or infection
What is the uterus comprised of?
- internally: smooth muscle (myometrium)
- externally: epithelial layer of endometrium lined with simple columnar epithelium
What is endometriosis?
- condition in which ectopic endometrial tissue is dispersed to various sites along the peritoneal cavity and beyond
- may be associated with ovaries or the attachments of the uterus and is often associated with severe period pain, infertility or both
What is the space between the cervix and vagina called? What does it help do?
- fornices
- helps to feel for other structures
What are the two openings of the cervix?
External os: hole that is visible on speculum examination and is the opening of the cervix into the vagina
Internal os: located at the internal opening of the uterus to the cervix
Describe the structure of the cervix
- a fibrous structure that can change through hormonal stimulation during menstrual cycle and pregnancy
- lined with simple columnar epithelium that produces cervical mucus which changes in consistency and pH depending on the menstrual cycle to help facilitate or prevent entry of sperm
- outside is lined with stratified squamous
What is the transitional zone of the cervix?
- area where the epithelium changes from cervical (columnar) to vaginal (stratified squamous)
- at most risk of malignant changes
How does the external os change when the pt. Has had babies
-becomes more slit-like
What is a cervical ectropian?
- when the inner lining of cervix cells (simple columnar) spread to the outside of the cervix
- occurs during menstrual cycle, when on contraception or when pregnant
What is the normal angle between the cervix and vagina known as?
Anteversion (if angle less than 180)
If angle more than 180 it is retroflexed
What is the normal angle between the cervix and uterus known as?
Anteflexion (if angle is less than 180)
If angle is more than 180 then it is retroflexed
How does the uterus expand as the fetus grows?
- GI organs will be compressed thus women may feel gastric-oesophageal reflux
- will also have constipation and urinary frequency due to pressure on pelvic organs
- ligaments are stretched which can cause pain in some patients
Where do the uterine and vaginal artery originate from?
Internal iliac artery
Anastomoses around this area
How is anteversion/anteflexion maintained?
-uterus is tethered at the round ligament which helps it to be in this position
How might a retroverted/retroflexed uterus manifest?
-patients wont realize it
Describe the vagina
- lined with stratified squamous epithelium
- contains glycogen which is metabolised by various bacteria such as lactobacilli
- lactobacilli regulates pH and converts glycogen into lactic acid to keep environment acidic to prevent infections such as candida
- vagina is adapted to expand during birth and its epithelium is designed to resist friction
- cannot provide any lubrication, but cervix can do that
Describe the vulva
- external genitalia which is comprised of the labia majora and labia Minorca
- vulval tumours can occur
During embryonic development, what are the three germ layers that arise?
-ectoderm, mesoderm and endoderm
Which germ layer primarily forms the reproductive tracts?
Intermediate mesoderm
Embryonic folding gives rise to a gut tube, which can be separated into foregut, midgut and hindgut. Which of these is an important anatomical location in the creation of the reproduction and urinary tracts and why?
- hindgut
- gives rise to the cloaca (a single opening)
- this eventually becomes the urogenital sinus (common opening for the reproductive and urinary systems)
What is the urogenital ridge?
-an area of intermediate mesoderm in the posterior abd wall that gives rise to the embryonic kidney and gonad
What is the gonad (indifferent) derived from?
-derived from intermediate mesoderm plus primordial germ cells (extragonadal)
What are primordial germ cells?
- special population of cells that arise from the yolk sac and migrate into the retroperitoneum, along the dorsal mesentery
- “seed” for the next generation
- develop soon after gastrulation
- will ultimately go on to produce sperm or ova once sexual maturation has occurred
Explain the differentiation of the gonads
- primordial germ cells migrate along retroperitoneum to gonad (indifferent)
- if gonad has Y chromosome then it will start forming seminiferous tubules and primordial germ cells will remain and will begin gametogenesis at puberty
- will form testis, medullar cords, and thick tunica albuginea but no cortical cords
- no Y chromosomes then gonad will differentiate into an ovary and the primordial germ cells remain as primordial follicles, which will then develop into oocytes at puberty
- will form ovary, and cortical cords but the medullary cords degenerate and no tunica albuginea
Explain the development of the internal genitalia
- male and female embryos have ducts which are used in the urinary system which are called mesonephric and paramesonephric ducts respectively
- presence of testes: androgens (testosterone) is produced, driving the development of epididymis and vas deferens by maintaining the mesonephric duct (Wolffian duct)
- mesonephric ducts NEEDS to be stimulated by male hormones in order to remain
- absence of testes: causes formation of the uterus, Fallopian tubes and part of the vagina as the mesonephric duct regresses BUT the paramesonephric duct (Mullerian duct) remains
- paramesonephric ducts needs no stimulation so it is “default”
- testes also produce Mullerian Inhibitory Substance (MIH) to prevent Müllerian duct from developing in males
- Wolffian=Wolf=alpha Male
- Mullerian=Mother=female
- Wolffian ducts fuse with testes so it is continuous and not open in peritoneum
- Mullerian duct is separate to gonad so there is a gap to the peritoneum
What happens when things go wrong in the development of internal genitalia?
- testosterone-treated female: exogenous androgen, supports the Wolffian duct, but no testes so no MIH is produced, thus Müllerian ducts develop
- androgen-resistant male: AIS (androgen-insensitivity syndrome), receptors for testosterone dont work, Wolffian ducts dont survive, but MIH is present so Müllerian ducts degenerate
How do the mesonephric (Wolffian) ducts develop?
- first acts as the duct for the embryonic kidney
- drains into the urogenital sinus
- urogenital sinus becomes urinary bladder
- surplus to requirement once true kidney develops
- Wolffian duct is maintained by testes derived androgens
- converted into the vas deferens and epididymis
- migrates with testes as they descend
- look at diagram
How do the paramesonephric (Mullerian) ducts develop?
- appear as invaginations of the epithelium of the urogenital ridge
- Caudally: make contact with the cloaca (urogenital sinus)
- Cranially: open into the abdominal cavity
- look at diagram
Explain the development of external genitalia
- indifferent stage of development
- Main components: genital tubercle (GT), genital folds, genital swellings
- male: GT elongates and genital folds fuse to form the spongy urethra, GT develops into glans penis, scrotum formed by fusion of genital swellings, influenced by testis-derived androgen hormones (dihydrotestosterone)
- female: no fusion occurs, development of labia majora and labia minors, GT develops into clitoris, urethra opens into the vestibule, formation of vulva
Explain the descent of the gonads for both female and males
- gonad is connected to what will be scrotum or labia by gubernaculum
- as a domino pelvic cavity increases in volume, gonad begins its descent inferiorly
- male: area of peritoneum pinches off to descend first, then the gubernaculum and testes follow behind all the way to scrotum, this area is called processis vaginalis and will close off
- female: gubernaculum attaches ovary inferiorly to labia-scrotal folds, ovary descends to pelvis, uterus has developed which forms a physical barrier and prevents further descent, gubernaculum remains as the round ligament (attaches to labia majora and goes through inguinal canal)
What are maldescended testes?
- when testes are not located in the scrotum but can be ectopic along the path it descends down
- important to examine a newborn and check
What is anatomically lateral to the vagina?
Ureter and levator ani muscle
