Week 5 Flashcards
What is the same about oogenesis and spermatogenesis?
Identical meiotic and mitotic divisions
When does oogenesis begin?
In utero but is suspended for many years
What happens to complete oogenesis?
Fertilisation
What is the earliest female germ cell?
Primordial
The primordial germ cell is capable of mitosis - where does it migrate to by week 6 of embryo development?
Genital ridge
What do the female germ cells oogonia give rise to?
Oocytes (completion of last pre-meiotic division)
What cells in the female germ line enter meiosis?
Oocytes
What is one of the first two products in the first stage of meiosis?
first polar body
What signifies sperm entry and the completion of 2nd meiotic division?
Presence of two polar bodies
How long does the ovarian cycle last for?
28 days
What phase in the ovarian cycle involves maturation of egg, ready for ovulation at midcycle-ovulation signals end of this phase?
Follicular phase
What phase of the ovarian cycle involves development of corpus luteum and induces preperation of reproductive tract for pregnancy (if fertilisation occurs)?
luteal phase
Before birth, what is the primary oocyte surrounded by?
Single layer of granulosa cells
What is each primary follicle capable of producing?
Single ovum
Until puberty - what happens to primary follicles?
Degenerate to scar tissue before ovulation
After puberty around how many eggs will be ovulated?
400 - rest undergo atresia
What ends the follicular phase?
Ovulation
What do follicular cells left behind ovulation undergo?
Luteinisation - transformation to hte corpus luteum
What does the corpus luteum secrete?
Progesterone
What secreted in follicular phase and what secreted in luteal phase are essential for preperation of uterine lining for implantation?
Follicular - oestrogen
Luteal - Progesterone
What does degeneration of corpus luteum signal the start of?
New follicular phase
The hypothalamus secretes GnRH which acts on what?
anterior pituitary
What does FSH from anterior pituitary stimulate?
Development of follicles
What does LH stimulate?
Follicle maturation, ovulation and development of the corpus luteum
FSH + LH stimulate what?
Secretion of oestradiol and ovulation
When LH and FSH are secreted in the follicular phase how do the 15 follicles mature?
Granulosa and theca cells develop
What do the theca cells produce which is converted by the granulosa (aromatase) to oestradiol?
Androgen
What does oestrogen suppress?
FSH production (selection of dominant follicle)
What do granulosa in the dominant follicle express?
LH receptors
What do high levels of oestrogen at mid cycle cause the hypothalamus to release?
GnRH which causes FSH and LH surge from anterior pituitary
Before ovulation what happens to the cumulus oophorus after increase in follicular fluid and number of granulosa?
Loosens and follicle wall weakens
After ovulation what happens to FSH and LH?
They fall
How can you detect ovulation?
Day 21 progesterone check
At 12 days - if there is no hCG production from an embryo, the corpus luteum degenerates forming the what?
Corpus albicans - progesterone and estrogen levels fall, removing negative feedback and cycle begins again
If pregnancy occurs, what does the developing embryo produce and what does it maintain?
hCG - maintains corpus luteum
What is the name of the class of steroid hormones which control the development and maintanence of female sexual characteristics?
Oestrogens
Where does glandular oestrogen synthesis occur?
In the granulosa and theca cells of the ovaries as well as corpus luteum
What are granulosa cells stimulated by to produce pregnenolone?
LH
What is the expression of aromatase and 17beta-HSD controlled by?
FSH stimulation
During extraglandular synthesis - what is expressed in non-gonadal sites and facilitates peripheral aronmitasation of androgens to estrone?
Aromatase
what is oligomenorrhea?
Reduction in frequency of periods to less than 9/year
What is primary amenorrhea?
Failure of menarche by age 16
What is secondary amenorrhea?
Cessation of periods for >6months in an individual who has previously menstruated
What two congenital problems can cause primary amenorrhea?
Turners and Kallmans
What two pituitary causes can result in secondary amenorrhea?
High PRL
Hypopiutuitarism
Give three symptoms of oestrogen deficiency?
Flushing
Libido
Dyspareunia
Give two clinical features of PCOS and androgen excess?
Hirtuism/acne
Name the 5 substances that are tested when investigating amenorrhea?
LH
FSH
Thyroid function
Prolactin
What investigation would you do if primary amenorrhea was present?
Karyotype
What type of hypogonadism involves problems with the ovaries, high LH/FSH (hypergonadotrophic hypogonadism) and an example is premature ovarian failure?
Primary hypogonadism
What type of hypogonadism involves problem with hypothalamus or pituitary, low LH/FSH (hypogonadotrophic hypogonadism) and an example is high PRL, hypopituitarism?
Secondary hypogonadism
What condition has amenorrhea, oestrogen deficiency and elevated gonadotrophins occuring
Premature Ovarian Failure (POF)
How is the diagnosis of POF made?
FSH more than 30 on 2 seperate occasions more than 1 month apart
Can radiotherapy/chemo cause POF?
Yes
What is the major defect in idiopathic hypogonadotrophic hypogonadism?
Inability to activate pulsatile GnRH secretion during puberty
Name the genetic disorder characterised by loss of GnRH secretion + anosmia or hyposmia?
Secondary hypogonadism: Kallmans syndrome
What seperates Kallmans and idiopathic hypogonadotropic hypogonadism?
Lack of smell in kallmans - MRI absence of olfactory bulbs
For the diagnosis of PCOS you need normal oestrogen levels and 2 of what three things?
- Menstrual irregularity
- Hyperandrogenism
- Polycystic ovaries
What does a polycystic ovary increase?
Testosteone
In PCOS what does increased testosterone do?
Increases LH and insulin resistance and hyperinsulinaemia
What sign does excess androgen cause in women?>
Hirtuism
What is an inherited group of disorders characterised by a deficiency in one of the enzymes needed for cortisol synthesis?
Congenital Adrenal Hyperplasia - autosomal recessive
What are 90% of CAH cases due to?
21alphahydroxylase deficiency
What are androgen secreting tumours frequently associated with signs of?
Virulisation and high testosterone above 5
Name three medications used to treat PCOS?
- contraceptive pill (regulates cucle, drecrease ovarian androgens)
- Anti-androgens - cyproterone acetate
- Local anti-androgens (efflornithine cream)
How do you treat late onset CAH?
Low dose glucocorticoid to suppress ACTH drive
What is the genetic defect in Turners syndrome?
46X0 instead of 46XX
Give four clinical features of Turners syndrome?
- Short stature
- Webbed neck
- Shielf chest with wide space nipples
- Cubitus Valgus
What congenital condition are these CVS problems found in: coarctation of aorta, bicuspid aortic valve and hypoplastic left heart?
Turnesr
What male hypogonadism involves low testosterone with high LH/FSH?
Primary hypogonadism
What is the most common congenital form of primary hypogonadism?
Klinefelters syndrpme 47XXY
Give five clinical features of Klinefelters sybdrome?
- Reduce testicular volume
- Gynaecomastia
- Eunochoidism
- Intellectual dysfunction
- Azoospermia
LH and FSH from pituitary react on ovaries to release what?
Estradiol
Progesterone
What type of pulses foes GnRH have to do to stimulate FSH?
Low frequency pulses (LH is high frequency)
In relation to hormone levels in menstrual cycle - when does estradiol peak?
Before ovulation
In relation to hormone levels in mesntrual cycle - when does progesterone peak?
Following ovulation
What does high oestrogen concentration inhibit and stimulate?
Inhibits FSH and prolactin
Stimulates LH
What does progesterone inhibit?
LH
How do you confirm regular cycles?
Midluteal day 21 serum progesterone more than 30
How do you manage hypothalamic anovulation?
Stabilise weight, pulsatile GnRH or FSH+LH daily injections. both need ultrasound monitoring of response
What acts as a co-gonadotrophin to LH?
Insulin
What dose of folic acid should be given pre treatment of PCOS?
400mcg
What are the three methods of ovulation induction in PCOS?
- Clomifene citrate, tamoxifen
- Gonadrotrophin therapy: daily injections
- Laparoscopic ovarian diathermy
When inducing ovulation in PCOS if a patient doesnt ovulate on Clomifene what is the other option?
Metformin
In a patient who has induced ovulation what does a lambda sign on ultrasound suggest?
Dichorionic twins - risk
In a patient who has induced ovulation what does a T sign suggest on ultrasound?
Monochorionic twins
What is the pathophysiology of twin-twin transfusion syndrome (risk when inducing ovulation in PCOS)?
Unbalanced vascular communications within placental bed
What levels are FSH/LH, oestrogen, serum prolactin and TFT in hyperprolactinaemia?
FSH/LH - normal
Oestrogen - low
Prolactin - raised > 1000
TFT - normal
Name a dopamine agonist used to treat hyperprolactinaemia#/
Cabergoline
Name three endocrine features anorexia nervosa gives?
- Low FSH
- Low LH
- Low oestradiol
What exacerbates PCOS?
Weight gain
Give three endocrine features of PCOS?
- High free androgens
- High LH
- Impaired glucose tolerance
Give three endocrine features of premature ovarian failure?
- High FSH
- High LH
- Low oestradiol
What could cause abdo/pelvic pain, vaginal discharge, dyspareunia, cervical excitation menorrhagia, dysmenorrhoea, infertility and ectopic pregnancy?
Hydrosalpinx due to pelvic inflammatory disease
What is endometriosis>?
Presence of endometrial glands outside uterine cavity
With endometriosis - what might a scan show?
Characteristic chocolate cysts on ovary
Name a congenital absence that can cause male infertility?
Cystic fibrosis
In obstructive causes of male infertility what happens to LH, FSH and testosterone?
- Normal Lh
- Normal FSH
- Normal testosterone
Give two clincal features of non-obstructive male infertility such as klinefelters?
- Low testicular volume
2. Reduced secondary sexual characteristics
What happens to LH, FSH and testosterone in non-obstructive male infertility such as klinefelters?
- High LH
- High FSH
- Low testosterone
What test is used to test tubal patency in women with infertility?
Hysterosalpingiogram
