Session 2 Flashcards
Fill in the blanks
What is the origin of the blood supply to the ovary?
Ovarian arteries - From the Aorta at L2/L3
Make a table describing the venous and lymphatic drainage of the ollowing structures:
Right ovary
Left ovary
Uterus
Cervix
Vagina
On the diagram label the fallopian (uterine tube) and its parts
On the diagram, label the ovarian artery, internal iliac artery, uterine artery, vaginal artery and internal pudendal artery
On the diagram label the structure 1-5
On the following label the:
Mons Pubis
Labia majora
Labia minora
Clitoris
Vestibule of the vagina
External urethral orifice
Anus
What is the function of the female reproductive tract?
Produce ova that can travel through the reproductive system so that fertilisation can occur
Describe the ovary, its function, relation to the testis and structure
The ovary is a paired organ, and is the place where oogenesis (production of an ovum) occurs, It is analogous to the testis in men. It has a fibrous outer structure called the tunica albuginea, like the testis, and has the same embryological origin. The ovary is fully enclosed in parietal peritoneum. It contains follicles that will be stimulated by FSH to produce a primary follicle, which will then mature to release an ovum.
Can cysts occur on the ovaries? If so what are they called and what are the possible complications?
The ovary may develop ovarian cysts, which are usually derived from follicles. These can be asymptomatic, or lead to complications such as torsion or rupture. Polycystic ovaries (with more than 10 cysts) is a common cause of infertility.
Can present as bloating, pain (acute pain from rupture or twist (torsion)). If large enough could cause urinary problems.
Which type of tissue do ovarian tumours most commonly arise from
Tumours of the ovary usually arise from epithelial components or germ cells
How does blood enter and leave the ovary
The suspensory ligament of the ovary allows passage of the ovarian artery and vein to the ovary. The origin of the ovarian artery is directly from the abdominal aorta, and the ovarian vein drains in the same way as the testicular veins. This ligamant also helps to suspend the ovaries.
What are the fallopian (uterine) tubes and what do they do? How are they specialised for their function?What can potentially go wrong?
This allows passage of the ovum to the uterus, and is the site where fertilisation occurs. The female reproductive tract opens into the peritoneal cavity. The fallopian tubes have fimbrae to allow a large surface area to ‘catch’ the ovum in the peritoneal cavity, and channel it to the infundibulum. This then continues to the ampulla, which is the most common site of fertilisation. Abnormal implantation can occur here giving rise to the most common form of ectopic pregnancy.
The fallopian tubes are lined with cilia, which enable transport of the ova to the uterus. These tubes can become blocked e.g. due to scarring in chronic infection, leading to infertility.
The wall of the fallopian tube is very convoluted and contains secretory cells which secrete substances helpful to both the egg and sperm
What is ectopic pregnancy?
A pregnancy in which the fetus develops outside the uterus, typically in a fallopian tube. Ectopic pregnancy is a medical emergency. The fallopian tubes are not adapted for implantation, and therefore the pregnancy is not viable and it can cause severe haemorrhage.
Describe the uterus and its ligaments
The uterus is divided into the fundus, the body and the cervix. The fundus usually expands during pregnancy, and is covered by parietal peritoneum.
There are a number of ligaments around the uterus:
The round ligament (derived from remnants of gubernaculum)
The ligament of the ovary (continuous with the round ligament, also derived from remants of gubernaculum)
Uterosacral ligament (connects uterus to sacrum)
The broad ligament (double fold of peritoneum) (attaches uterus to pelvic side walls)
The broad ligament can be subdivided according to its surrounding structures:
Mesovarium – surrounding the ovary
Mesometrium – between the pelvic wall and the uterus
Mesosalpinx – surrounding the fallopian tubes
How is blood supplied to the uterus? Where is this artery in comarison to the ureter?
The uterine artery originates from the internal iliac artery, and runs between the layers of the broad ligament. Importantly, the ureter runs under the uterine artery (‘water under the bridge’).
Describe the pouches that are next to the uterus. Why are they clinically important?
The bladder is anterior to the uterus, and the rectum is posterior to the uterus. The peritoneal reflections between these organs are known as the vesicouterine pouch between the uterus and the bladder anteriorly, and the rectouterine pouch (‘Pouch of Douglas’) between the rectum and the uterus posteriorly. These are important clinically as they can be a site of fluid collection e.g. in haemorrhage or infection.
Describe the internal composition of the uterus
The uterus internally is comprised of smooth muscle (myometrium) and an epithelial layer of endometrium, lined with simple columnar epithelium. Both of these structures undergo changes during the menstrual cycle, which will be covered in more depth when we look at the menstrual cycle.
What is endometriosis?
Clinical correlation box Endometriosis is a condition in which ectopic endometrial tissue is dispersed to various sites along the peritoneal cavity and beyond. It may be associated with the ovaries or the attachments of the uterus and is often associated with severe period pain (dysmenorrhoea), infertility or both.
What is the cervix? Describe its structure. Where is cervical cancer most likely to arise?
This is a fibrous structure that can change through hormonal stimulation during the menstrual cycle. It also changes during pregnancy and delivery to allow birth of the fetus. Pathology of the cervix such as cervical cancer can be found via speculum examination. The ‘hole’ that is visible on speculum examination is the external os, the opening of the cervix into the vagina, with the internal os located at the internal opening of the uterus to the cervix.
The cervix is 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.
The zone close to the external os is called the transitional zone, where the epithelium changes from cervical to vaginal epithelium, and is most at risk of malignant changes. These early malignant changes can be identified through cervical screening.
The Cervix is a part of the uterus
What is the difference between anteversion and anteflexion?
The normal angle between the cervix and the vagina is known as anteversion, and the normal angle between the cervix and the uterus is known as anteflexion.
Describe the lining of the vagina and its adaptations
The vagina is lined with stratified squamous epithelium. It contains lactobacilli as part of its flora to regulate the pH and keep the environment acidic to prevent infections such as candida (thrush). It is adapted to expand during birth and its epithelium is designed to resist friction e.g. during sexual intercourse. It cannot provide any lubrication and is therefore dependent on secretions from the cervix.
Describe how differentiation of he gonad occurs
The primordial germ cells migrate along the retroperitoneum to the gonad, which at this point is indifferent (neither ‘male’ nor ‘female’). The karyotype of the fertilised oocyte determines the karyotype of the primordial germ cells (XX or XY), and will therefore determine whether the gonad differentiates to become male or female.
The Y chromosome contains a SRY gene. Genes in that region cause differentiation of the gonad into a testis. This leads to the formation of seminiferous tubules, and the primordial germ cells remain, and will begin gametogenesis at puberty. Without those genes, the gonad will differentiate into an ovary. No tubules develop, however the primordial germ cells remain as primordial follicles, which will then develop into oocytes at puberty.
Describe the duct systems involved in reproductive development in the embryo to form the internal genitalia
Both male and female embryos have a pair of ducts that are used in the development of the urinary system. These are called the mesonephric ducts and paramesonephric ducts.
The presence of testes will produce androgens (testosterone), which then drive the development of the duct system in men; namely the epididymis and vas deferens, by maintaining the mesonephric duct (‘Wolffian duct’). The mesonephric duct needs to be stimulated by male hormones in order to remain. Without male androgens, the mesonephric duct degenerates.
The absence of testes will cause formation of the female internal genitalia; namely the uterus, fallopian tubes and part of the vagina, as the mesonephric duct regresses, but the paramesonephric duct (‘Mullerian duct’) remains. Unlike the mesonephric duct, this needs no stimulation and is therefore the ‘default’. In fact, the testes also produce ‘Mullerian Inhibitory Substance’ (MIH) to prevent the Mullerian duct from developing in males.
The mesonephric ducts fuse with the gonad (testes), therefore the male reproductive system is continuous and not open in the peritoneum.
Think Wolffian – Wolf – “alpha Male”
Think Mullerian – Mother – female
However, the Mullerian duct is separate to the gonad, therefore the two do not meet and there is no direct connection, hence there is a gap in communication within the abdominal cavity. This relates to the anatomy we see in adulthood.
How does the external genitalia form in males and females?
The common elements of the undifferentiated external genitalia are the genital tubercle, the genital folds and the genital swellings.
In the male the genital tubercle elongates and genital folds fuse to form the spongy urethra. The genital tubercle develops into the glans penis. This is influenced by tetsis-derived androgen hormones in particular, dihydrotestosterone (more potent androgen). Fusion of the genital swellings form the scrotum.
No fusion occurs in the female so genital tubercle develops into the clitoris, genital swellings become labia majora and genital folds become labia minora. Urethra opens into the vestibule
Describe the descent of the testes
Gubernaculum attaches the gonad inferiorly to the labio-scrotal folds. As the abdominopelvic cavity increases in volume the gonad begins its descent inferiorly. Testes invaginate into the anterior abdominal wall into the scrotum. The layers of the abdominal wall which the testes have invaginated into go on to form the layers of the spermatic cord.
An area of the peritoneum pinches off to descend first, then the gubernaculum and testis follows behind all the way to the scrotum. This area of peritoneum is called the processus vaginalis, and normally this closes off.
What might cause the external os to look different?
Cervical ectropion is normal and can be seen during different stages of the menstrual cycle and during pregnancy
Describe how the angles between the axis of the uterine body, axis of the vagine and axis of the cervix can change
if angle between axis of uterine body and axis of cervix is below 180 degrees the uterus is anteflexed and if above then it is retroflexed.
If the angle between the axis of the uterus and the axis of the vagina is below 180 the cervix is anterverted and if above 180 then its retroverted.
The most common position for the uterus is anteflexed and the most common position for the cervix is anteverted
The round ligament helps to tether the uterus in its anteflexed/anteverted position.
If women have retrovered/retroflexed uterus then it can present with dyspareunia (difficult or painful sexual intercourse) but mostly asymptomatic
Describe the external genitalia of a female
Describe the indifferent stage of internal genitalia development
Mesonephric ducts develop in both male and female embryos
Paramsonephric ducts develop in both male and female embryos
Both ducts end at the urogenital part of the cloaca
Describe paramesonephric duct development
Paramesonephric ducts (mullerian ducts) appear as invaginations of the epithelium of the urogenital ridge.
Caudally: Make contact with the cloaca (urogenital sinus)
Cranially: Open into the abdominal cavity
In the absence of MIH they grow into the cavity and towards each other. they draw with them the peritoneum which forms the broad ligament. initially there is a septum but this is resolved to form a single cavity with two tubes attached and this is the uterus and the fallopian tubes. CRanial ends are open to the peritoneal cavity.
Caudally there’s an interaction between the paramesonephric ducts and the urogenital sinus (endoderm of hindgut) which gives rise to the vagina. upper 1/3 derived from paramesonephric duct and lower 2/3 from urogenital sinus.
