Week 1 Flashcards
What do the ovaries produce?
Oocytes and hormones (oestrogen, progesterone)
Why is the surface of ovaries scarred?
Wound healing process of menstruation
What arteries supplies the ovaries and where does it originate?
Ovarian arteries
Arises from the aorta at the level of the renal artery
What veins drains the ovaries and where do they empty?
Ovarian veins
Right - IVC
Left - renal vein
What is the lymphatic drainage of the ovaries?
Aortic nodes
What are the 3 main ligaments of the ovaries?
Broad - peritoneal sheet draped over uterus and tubes
Ovarian - fibrous cord, links ovary to uterus
Suspensory - links lateral wall of pelvis to ovary, carries ovarian artery and vein
Which ligament of the ovary carries the ovarian artery and vein?
Suspensory ligament
What are the rectouterine and uterovesical pouches and what is their importance?
Rectouterine - between uterus and rectum; deep
Uterovesical - between uterus and bladder; shallow
Peritoneal infection will spread to these areas which are very difficult to treat
Associated with endometriosis
What is the infundibulum of the uterine tube?
Funnel-shaped opening to peritoneal cavity, fringed by fimbriae
What is the ampulla of the uterine tube?
Middle section where fertilisation occurs, intricate folds in mucosa
What are the approximate measurements of the uterus?
7-8cm long, 5cm wide, 2.5cm thick
Highly variable
What is the internal os of the uterus?
Opening between the body of the uterus and the cervical canal
What is the external os of the uterus?
Opening between the cervical canal and vagina; different appearance post-childbirth (bounded by lips, more slit-like)
What is the fundus of the uterus?
Rounded superior portion, extends above the level of the uterine tubes
What is the isthmus of the uterus?
Narrowing between the body and canal
Which rare condition is caused by a malformation resulting in formation of 2 uterine bodies?
Bicornuate uterus
What is the normal anatomical position of the uterus?
Anteflexed - uterus body is bent forwards on the cervix
Anteversed - whole uterus is bent forwards at a right angle to the vagina
What is the blood supply and lymphatic drainage of the uterus?
Arterial - uterine artery (branch of internal iliac artery)
Venous - uterine vein (drains to internal iliac vein)
Lymphatics - body drains to para-aortic nodes, cervix drains to internal iliac nodes
What is the prostatic utricle?
Small dead-end channel found in the male prostatic urethra
Remnant of female vagina
What is the epididymis of the male reproductive tract?
Coiled structure
Part of the duct system allowing sperm to travel out of the body via the urethra
What is the vas deferens of the male reproductive tract?
Starts in the testes, loops over the bladder and enters the prostate
Carries sperm and semen for ejaculation
What is the bulbourethral gland of the male reproductive tract?
Mucus secreting gland
Small, located below prostate
What is retrograde ejaculation?
Backflow of semen to bladder where sperm are damaged by the acidic environment; negative consequences for fertility
What are the layers of the wall of the scrotum?
Skin Dartos fascia and muscle External spermatic fascia Cremasteric muscle and fascia Internal spermatic fascia
What is the function of the cremaster muscle?
Contracts/relaxes to raise/lower testis in cold/warm temperatures
What is the cremasteric reflex?
Stroking the upper inner thigh will cause the testes to rise on the same side
What is the tunica vaginalis of the testes and what is its clinical importance?
Closed sac of peritoneum with visceral and parietal layers between which exists a film of peritoneal fluid
Excess fluid forms a hydrocele
Outline the pathway of the duct system within the testes
Seminiferous tubules → straight tubule → rete testes → efferent ductules → epididymis → vas deferens
What is the blood supply and lymphatic drainage of the testes/scrotum?
Arterial - testicular artery
Venous - pampiniform plexus (to testicular vein and then IVC on right/renal vein on left)
Lymphatics - testis to para-aortic nodes, scrotum to inguinal nodes
What epithelium lines the epididymis and how is this adapted to its function?
Pseudostratified columar epithelium with stereocilia
Stereocilia increase surface area for fluid absorption so that composition can be monitored and adjusted
What type of contraction occurs in the vas deferens?
Peristalsis
What is the enlargement at the end of the vas deferens called and what outpouching lies here?
Ampulla
Seminal vesicle adds secretions
What is the function of the seminal vesicles?
Secretes an alkaline viscous fluid which helps to neutralise the acid in the female tract to protect sperm
What does seminal fluid contain?
Alkaline fluid, fructose (used for sperm ATP production), prostaglandins (sperm motility/viability and female contraction)
How is the ejaculatory duct formed and where does it extend to?
Seminal vesicle duct joins with the vas deferens
Penetrates prostate and empties into the urethra
What does the prostate gland do?
Secretes a slightly acidic fluid containing citrate (used by sperm for ATP production), acid phosphatase and proteolytic enzymes which liquefy coagulated semen
Which embryonic layer is the urogenital tract derived from?
Intermediate mesoderm
How many kidney structures form during embryonic development and what are they called?
3 Pronephros (cervical), mesonephros (abdominal), metanephros (pelvic)
In what week does the pronephros start to form?
Week 4
What is the pronephros?
Mesoderm solidifies into 7-10 cell clusters in the cervical region which are rudimentary and non-functional and regress
What is the mesonephros?
Upper thoracic and lumbar formation of unsegmented tubule shapes which drain into ducts and are technically functional
Contributes supporting cells to the genital ridge
Mesonephric duct forms and remains when mesonephros regresses
When is the metanephros formed and functional?
Appears in week 5
Functional by week 11
In what 2 parts is the metanephros formed?
Ureteric bud (outgrowth of mesonephric duct) Metanephric cap (circular mesenchymal structure around bud)
What is the cloaca?
Posterior orifice acting as a drain for urinary, reproductive and digestive tracts
Describe the role of the urorectal septum in embryological development
Urorectal septum divides the cloaca by fusion with the cloacal membrane to form the anterior urogenital sinus (bladder) and posterior rectal/anal canal
What forms the bladder in embryological development?
Urogenital sinus and caudal mesonephric duct (trigone)
What embryonic layer lines the bladder?
Endoderm
When are male/female morphological characteristics acquired in the embryo?
Week 7
What reproductive apparatus is present at the indifferent stage?
1 pair of gonads
2 pairs of genital ducts - lateral paramesonephric/Mullerian ducts (female) and mesonephric/Wolffian ducts (male)
What do the mesonephric ducts become in the male?
Form vas deferens and ejaculatory duct under the influence of testosterone
What do the paramesonephric ducts become in the female?
Form uterine tubes, uterus and superior vagina
Why do the paramesonephric ducts degenerate in the male?
Due to the action of anti-Mullerian hormone secreted by Sertoli cells
Why do the mesonephric ducts degenerate in the female?
Lack of stimulation from testosterone
In which week do the indifferent gonads appear?
Week 5
Where do primordial germ cells originate from and what do they form?
Yolk sac
Primitive sex cords
How are the primitive gonads formed?
Subset of epiblast cells move into the yolk sac for room to develop and then move back to urogenital ridge via dorsal mesentery to form the primitive gonads
Outline the development of the male gonads
Y chromosome encodes SRY testis determining factor → sex cords become horse-shoe shaped and break up into tubules → Leydig cells produce testosterone and Sertoli cells produce anti-Mullerian hormone → tunica albuginea forms and separates cords from surface epithelium → rete testes and mesonephric ducts fuse to form vas deferens
What characteristic of the testis cords changes in puberty?
Solid until a lumen is formed in puberty, giving rise to seminiferous tubules
Outline the development of the female gonads
Wnt 4 ovary determining gene
Primordial germ cells divide by mitosis → pool of oogonia - enter meiotic arrest at beginning of 4th month of gestation, now oocytes which become associated with follicular cells (primordial follicles)
In what week do the primordial germ cells migrate to the urogenital ridge from the yolk sac?
Week 6
In which week do the external genitalia begin to develop?
Week 3
Outline the development of the external genitalia
Pair of cloacal folds develop around cloacal membrane and join to form the genital tubercle → cloacal folds are subdivided into urethral folds and anal folds → genital swellings appear on each side of the urethral folds
How does the urethra develop?
Genital tubercle elongates into phallus → phallus pulls urethral folds forward → urethral folds form lateral walls of urethral groove and close over urethral plate to form the penile urethra
How does the lower vagina develop?
Sinovaginal bulbs grow out from urogenital sinus → bulbs fuse to form vaginal plate → hollows to form a cavity
What do the urogenital folds become in the male and female?
Male - ventral aspect of the penis
Female - labia minora
What do the genital swellings become in the male and female?
Male - scrotum
Female - labia majora
What does the gubernaculum become in the female?
Ovarian/round ligament
What is vaginal atresia?
Failure of the vagina to become hollow, no lumen development
What causes hypospadias?
Failure of urethral folds to fuse, causing holes to develop at any point along the penis
What is Kleinfelter’s syndrome?
47XXY
Leydig cells do not produce enough testosterone causing low sperm production, internalised testes and female appearance
What is testicular feminising syndrome?
46XY
Genetic male, external female
Testosterone is produced but X chromosome mutation causes a deficiency in receptors
What is Turner’s syndrome?
X0
Primordial germ cells degenerate at the urogenital ridge, causing failure in gonadal development and infantile genitalia
Where are peritubular myoid cells found?
Outside the basement membrane at the outer edge of seminiferous tubules in the testes
Which cells are responsible for the blood-testis barrier?
Sertoli cells
What does the blood-testis barrier do?
Prevents autoimmune destruction of developing gametes
What cells are found resting on the basement membrane of seminiferous tubules?
Sertoli cells and spermatogonia/stem cells
By which process do spermatogonia, primary spermatocytes and secondary spermatocytes divide?
Spermatogonia - mitosis
Primary - meiosis I
Secondary - meiosis II
Where in a cross-section of a testes would Leydig cells be found?
In the interstitial tissue between seminiferous tubules where they are associated with blood vessels to allow testosterone secretion into the bloodstream
What are the histological features of Leydig cells?
Ovoid nuclei, pink cytoplasm with H&E, punctate chromatin
What sheath surrounds the 2 corpora cavernosa of the penis?
Tunica albuginea
What runs through the middle of the corpus spongiosum of the penis?
Penile urethra
What is the functional difference between the corpus spongiosum and cavernosa?
Spongiosum erectile tissue network is finer to avoid compression of the urethra on erection and the tunica albuginea is also thinner
What types of epithelium line the urethra?
Uroepithelium → pseudostratified columnar → stratified squamous
What is contained in the spermatic cord?
Veins, arteries, connective tissue and vas deferens
What are the 3 layers of smooth muscle in the wall of the vas deferens?
Middle circular, inner and outer longitudinal
What is the stroma of the prostate composed of?
Smooth muscle cells and fibrous tissue
What type of epithelium is present in the prostate?
Cuboidal/low columnar
Associated with carcinoma
What can be seen in some of the secretory units of the prostate and what is their function?
Eosinophilic/amyloid bodies - represent thickened secretion
What type of joint is the symphysis pubis?
Cartilaginous
What is the inlet of the pelvis?
A line drawn between the upper border of the symphysis pubis and sacral promontory which separates the abdominal and pelvic cavities
What is the pelvic outlet?
A line drawn between the lower border of the symphysis pubis and the tip of the coccyx
What is the pelvic diaphragm?
Muscular sheet limiting the pelvic cavity below
What type of joint is the sacroiliac joint?
Synovial joint
What is the linea terminalis?
Composed of the arcuate line of the ilium and the pectineal line of the pubis
Divides false/greater pelvis from the true/lesser pelvis
What muscles attach to the iliac crest?
External and internal oblique muscles, transversus, quadratus lumborum
What is spermatogenesis?
The process by which immature stem cells (spermatogonia) proliferate and differentiate into mature spermatozoa
What is spermiogenesis?
Differentiation process at the end of spermatogenesis
Spermatids mature into spermatozoa
How long does spermatogenesis take?
64 days
What are the 3 types of spermatogonia?
A dark, A pale and B
What is the function of A dark spermatogonia?
Backup in case of severe damage to spermatogenesis (e.g. irradiation, cytotoxic drugs)
Where does the proliferative stage of spermatogenesis take place?
Basement membrane
What are the stages between primary spermatocyte and secondary spermatocyte?
Leptotene, zygotene, pachytene, diplotene
At which stage of spermatogenesis do the cells move off the basement membrane and through the blood-testis barrier?
Leptotene
Outline the process of spermiogenesis
Nuclear condensation → acrosome forms from golgi → tail develops from centriole → cytoplasm re-distributes (residual body lost) → mitochondria re-arrange in middle piece
Where in the spermatozoa are mitochondria located?
Mid-piece
Outline the hormonal control of spermatozoa production
Hypothalamus secretes GnRH → anterior pituitary releases LH and FSH → stimulation of testis growth and function
What does LH stimulate in the male?
Leydig cells to secrete testosterone
What does FSH stimulate in the male?
Sertoli cells to produce spermatozoa
What does testosterone stimulate in the male?
Sertoli cells and peritubular myoid cells
Maintains prostate and seminal vesicles
Which cell type drives spermatogenesis?
Sertoli cells
Which hormones stimulate differentiation of spermatogonia to spermatocytes?
FSH and testosterone
What crucial role does testosterone play in spermatozoa production?
Passage of spermatocytes through meiosis
Spermiogenesis stimulation
What role does the epididymis play in spermatozoa maturation?
Non-motile non-fertile sperm enter at the head and become functional as they travel down to the tail where they are stored
What is an endocrine disruptor?
An exogenous chemical which can disrupt normal endocrine function, often with a similar structure to endogenous hormones
What are the 3 ways endocrine disruptors can act?
Act as an agonist (too much hormone/inappropriate activation)
Act as an antagonist (prevents action of hormone)
Interfere with metabolic processes (affect synthesis/breakdown of natural hormone)
What kind of problems can be caused by endocrine disruptors?
Reduced fertility, developmental abnormalities, menstrual problems, early puberty, brain/behavioural problems, cancer
What are phthalates?
Man-made chemicals used to soften and increase flexibility of polyvinyl chloride plastics (e.g. enteric tablet coatings, insect repellent, cosmetics)
What conditions are linked with testosterone dysgenesis syndrome?
Cryptorchidism, low sperm count, cancer, intrauterine growth restriction, hypospadias - altered foetal testis development
What is diethylstilbestrol and what are its effects?
Synthetic oestrogen
Banned endocrine disruptor - prescribed to prevent spontaneous abortion and promote foetal growth but resulted in developmental problems and vaginal cancer
When in intrauterine life do the testes descend?
7 months
What is the mesovarium?
Portion of the broad ligament of the uterus that suspends the ovaries
What are the 2 types of follicular cells in the ovary and what are their functions?
Granulosa cells - inside follicle, produce aromatase which converts androgen to oestrogen
Theca cells - interna (produce androgens from cholesterol and contain blood vessels), externa (collagenous)
What is atresia in relation to the ovary?
Spontaneous degeneration of a follicle at any stage; granulosa cells contract and spill into the antrum
What happens in premature ovarian failure/insufficiency?
Failure of ovaries to produce eggs
What are the histological features of a corpus luteum in pregnancy?
Cells filled with lipids as a source of cholesterol for formation of progesterone
What is the main hormone of pregnancy?
Progesterone
What happens to the corpus luteum if fertilisation does not occur?
Degenerates into the corpus albicans
What epithelium is present in the vagina and how is it adapted to its function?
Stratified squamous non-keratinised (same as oesophagus)
Protects against wear and tear during intercourse and childbirth etc.
What causes the vaginal mucosa to be acidic?
Mucosa has large stores of glycogen which produce organic acids on decomposition and create a low pH environment for protection
Where does vaginal mucus come from?
Mostly produced in the cervix and moves down to the vagina for lubrication
What is the location and function of Bartholin glands?
Vagina
Mucus production during intercourse
What type of mucus is best for sperm motility?
Egg-white
Where are the bases of the uterine glands found?
Stratum basalis of the endometrium
Which arteries supply the stratum functionalis?
Spiral arteries
What are the subdivisions of the endometrium?
Stratum basalis
Stratum functionalis - stratum compactum, stratum spongiosum
Which arteries supply the stratum basalis?
Straight arteries
What is the thickest layer of the uterine wall and why?
Myometrium
Required to sustain and expel a foetus
What type of epithelium is present in the uterus?
Secretory columnar
What histological changes occur in the uterus during the secretory phase of the menstrual cycle?
Glands fill with carbohydrate-rich nutrients for foetal nourishment
Spongy appearance of endometrium
Outline what happens in the uterus during menstruation (no fertilisation)
No pregnancy → no embryo → no hCG → no corpus luteum → no progesterone → spiral arteries
become compressed and shrink → no blood supply to top functional layer → ischaemia and necrosis
of tissue and stasis of blood → pressure on arteries is relieved → arteries spring back and backed up
blood washes tissue away → menstrual period
Why does menstruation last 5-7 days?
Process of tissue necrosis and blood stasis occurs in patches
Where does fertilisation take place?
Ampulla of uterine tubes
What type of epithelium is present in the uterine tube?
Ciliated columnar and secretory
What are the main histological characteristics of the ampulla and interstitial part of the uterine tube?
Ampulla - complex mucosal folding, wide lumen
Interstitial - thick wall, small lumen, mucosa folded into low ridges, muscularis has inner circular and outer longitudinal muscle
How long can sperm survive in the female reproductive tract?
Up to 7 days
Where are steroid hormones produced?
Gonads, adrenal glands and placenta smooth ER and mitochondria
Circulating oestrogens are a mixture of what hormones?
Oestrone and oestradiol
What is the function of oestrogen?
Development of female secondary sex characteristics
What androgens are produced in the female and where does this occur?
Androstenediol, DHEA and small amounts of testosterone
Ovaries and adrenal glands
What proportion of testosterone, androstenedione, DHEA and DHEAS are produced in the adrenal gland compared to the ovary
Adrenal - 25% testosterone, 50% androstenedione, 90% DHEA, 100% DHEAS
Ovary - 25% testosterone, 50% androstenedione, 10% DHEA
Where are progestins produced and what are their functions?
Corpus luteum of ovary, adrenal glands, placenta in pregnancy
Endometrial development, maintenance of pregnancy, mammary gland development
What enzyme is deficient in congenital adrenal hyperplasia and what does this condition cause?
21-hydroxylase (or 11β-hydroxylase)
Ambiguous genitalia, precocious puberty, anovulation, hirsutism
What happens in aromatase deficiency and excess?
Deficiency - prevents oestrogen synthesis; ambiguous genitalia
Excess - high conversion of androgens to oestrogens; feminisation of male genitalia
Outline the hormonal control of female reproductive endocrinology
Hypothalamus secretes GnRH in a pulsatile manner → anterior pituitary releases FSH and LH → ovary (and placenta) respond to levels of the gonadotrophins and secrete steroid sex hormones
What cells in the hypothalamus produce GnRH?
Neurosecretory cells
What does FSH do in the female?
Initiates recruitment of follicles and supports their growth (particularly granulosa cells)
What does LH do in the female?
Surge triggers ovulation (supports theca cells)
Outline the main details of the menstrual cycle
28 days long, ovulation at day 14
Pre-ovulatory follicular phase
Post-ovulatory luteal phase
What are the levels of progesterone and oestrogen during the follicular phase of the menstrual cycle?
Progesterone - low
Oestrogen - rising due to conversion of androgens to oestrogens via aromatase
How does a primordial follicle develop into a primary follicle?
BMP 4 and 7 from stromal cells
KIT ligand from oocyte signal recruitment of stromal cells to theca cells
How are primordial and primary follicles differentiated?
Primordial - thin, flattened, single layer of cells
Primary - >1 layer of cells, zona pellucida visible
How is a secondary follicle characterised?
Presence of a fluid-filled antrum, increase in follicular cells, granulosa and theca cell differentiation and receptor development (FSH, oestrogen, androgen)
What happens to hormone levels when follicles are recruited?
Recruited follicles increase oestradiol (via androgen conversion) → LH and FSH synthesis increased but secretion is inhibited (FSH more inhibited) → inhibin produced by developing follicles which inhibits FSH secretion but not LH → levels of oestrogen increase exponentially
At what point in the menstrual cycle does positive feedback occur?
When oestrogen levels are very high, days 12-14
What affect does oestrogen have on the endometrium?
Proliferative phase
Thickens stroma, elongates uterine glands, stimulates growth of spiral arteries
What happens to hormone levels at ovulation?
Increase in oestrogen causes increased responsiveness of pituitary to GnRH → oestrogen peaks and progesterone levels increase → high oestrogen triggers LH secretion → stored LH released in massive amounts (surge) with smaller increase in FSH → ovulation occurs → oestrogen decreases, progesterone continues to increase
How does the LH surge cause ovulation?
Stimulates enzymes involved in breakdown of follicle wall, causing release of oocyte in 16-32 hours
Also triggers completion of first meiotic division of oocyte within 36 hours of ovulation
What can the 21 day progesterone test be used for?
Check if ovulation is occurring in women worried about fertility
Which phase of the menstrual cycle is most constant between women?
Luteal phase, averages 14 days
Which hormone is secreted by the corpus luteum and when does this peak?
Progesterone (and some oestrogen)
6-8 days post-ovulation
What effects does inhibin have in menstruation?
Inhibition of FSH and LH secretion which causes regression of the corpus luteum and subsequent decrease in progesterone
What changes are observed in the vagina in response to hormonal changes in the menstrual cycle?
Early follicular - low oestrogen, epithelium thin and pale
Late follicular - increasing oestrogen, epithelium thickens
Luteal - shedding
What changes are observed in the cervix in response to hormonal changes in the menstrual cycle?
Late follicular - increased vascularity, watery mucus to faciliate sperm, external os opens slightly
Luteal - increased progesterone, mucus thickens
What mechanisms are used by contraceptives to prevent pregnancy?
Change in cervical mucus or prevention of ovulation
What is polycystic ovarian syndrome and what causes it?
Common endocrine abnormality affecting women in which there is a complex hormonal imbalance between LH and FSH
Presents with infertility, lack of ovulation/menstruation, weight gain, acne, hirsutism
Loss of negative feedback - continuous oestrogen production causes elevated LH which increases androgen production
Where does the spermatic cord run?
Through the deep inguinal ring, inguinal canal and superficial inguinal ring
Where does the spermatic cord end?
Scrotum
What are the contents of the spermatic cord?
Ductus deferens, testicular artery (and artery of the ductus deferens and the cremasteric artery), pampiniform plexus of veins, sympathetic nerves on arteries, sympathetic and parasympathetic nerves on ductus deferens, lymphatics
What do the sacral foramina transmit?
Spinal nerves (anterior and posterior rami)
What are the ligaments of the sacroiliac joint?
Sacrospinous and sacrotuberous ligaments
What is the inguinal ligament?
Thickened lower border of the aponeurosis/flattened tendon of the external oblique muscle
What are the attachments of the inguinal ligament?
Anterior superior iliac spine and pubic tubercle
What is the main difference between the male and female pelvis?
The shape of the superior pelvic aperture - heart-shaped in the male, rounded in the female
What are the alae of the sacrum?
Lateral areas of the base of the sacrum
What 2 clinical conditions of the prostate can affect older men?
Prostatic hypertrophy and carcinoma
What is the spermatic cord?
Collection of structures running to and from the testis which suspends them in the scrotum
What complication may occur from a ‘back street’ abortion?
Perforation of the rectouterine pouch between the uterus and the rectum leading to infection of the peritoneum
What is varicocele?
Abnormal enlargement of the pampiniform venous plexus in the scrotum
What clinical conditions are associated with the prostatic stroma and prostatic epithelial cells?
Stroma - BPH
Epithelium - prostatitis
