Reproductive Endocrinology & Disorders Flashcards
where does oogenesis begin?
in utero (as foetus)
when is oogenesis completed?
fertilisation
when does oogenesis cease?
at menopause
what is a primordial germ cell?
earliest recognisable germinal cell
what is a primordial germ cell capable of?
mitosis
where does a primordial germ cell migrate to and when?
genital ridge by week 6 of embryo development
what is oogonia?
completion of last pre-meitotic division to oocytes
what are primary oocytes?
1st meiotic division
what are secondary oocytes?
2nd meiotic division
how many types of polar bodies are there?
2 (sperm & egg)
what do both polar bodies have in common?
relatively small
contain little cytoplasm
what does the presence of 2 polar bodies signify?
sperm entry & completion of 2nd meiotic division (fertilisation)
when is the number of eggs in a female highest?
before birth
what happens to the number of eggs in a foetus just before birth?
rapidly decreases
can an ovary produce eggs after the age of 20/30 if it has been damaged?
no as no stem cells present - born with finite number of eggs
what is the average length of ovarian cycle?
28 days
how many phases does an ovarian cycle have & what are they?
2
- follicular phase
- luteal phase
what happens during the follicular phase?
Maturation of egg, ready for ovulation at midcycle – ovulation signals end of follicular phase
what happens during the luteal phase?
Development of corpus luteum.
Induces preparation of reproductive tract for pregnancy (if fertilisation occurs)
what is a primary follicle?
Before birth, the primary oocyte is surrounded by a single layer of granulosa cells
what is each primary follicle capable of producing?
a single ovum
what happens to primary follicles until puberty?
degenerate to scar tissue at some stage before ovulation
atresia
scar tissue
luteinisation
transformed to the corpus luteum
what hormone does corpus luteum produce?
progesterone
which hormone is secreted in the follicular phase?
oestrogen
which hormone is secreted in the luteal phase?
progesterone
if no fertilisation has occurred how long would the corpus luteum survive?
no longer than 14 days after ovulation
what signals the start of new follicular phase?
degeneration of corpus luteum signals
what hormones does the anterior pituitary secrete?
FSH
LH
what does the hypothalamus secrete & what does it act on?
GnRH
anterior pituitary
what dies the FSH act on?
ovary
what does LH act on?
ovary
what does FSH do?
stimulates development of follicles
what does LH do?
stimulates follicle maturation, ovulation & development of the corpus luteum
what do FSH + LH stimulate?
secretion of oestradiol & ovulation
what do theca cells produce?
androgen
what is androgen converted to & where?
to oestradiol
by the granulaosa
what does oestrogen do to the anterior pituitary?
suppresses FSH production
what forms the corpus luteum?
remaining granulosa that have proliferated
what do theca cells convert androgen to?
oestrogen
oligomenorrhea
reduction in frequency of periods to less than 9/year
primary amenorrhoea
failure of menarche by the age of 16 years
secondary amenorrhea
cessation of periods for >6 months in an individual who has previously menstruated
menarche
first menstrual cycle
what are the physiological causes of amenorrhoea?
pregnancy
post-menopausal
amenorrhea
abnormal absence of menstruation
what should you consider in primary amenorrhea?
congenital problems
what ovarian problems can cause secondary amenorrhoea?
PCOS
Premature ovarian failure
what are oestrogens?
class of steroid hormones which control the development & maintenance of female sexual characteristics
where does glandular oestrogen synthesis?
in the granolas & theca cells of the ovaries as well as the corpus luteum
what is the rate limiting step of the production of oestrogen?
conversion of cholesterol to pregnenalone
what does oestrogen production fluctuation match?
thickness of endometrium
what uterine problems can cause secondary amenorrhoea?
uterine adhesions
uterine adhesions
problems with shedding endometrium due to adhesions
what pituitary problems can cause secondary amenorrhoea?
high PRL
hypopituitarism
give some examples of oestrogen deficiency
flushing
libido
dyspareunia
dyspareunia
difficult or painful sexual intercourse
anosmia
loss of sense of smell
what would anosmia suggest?
kallman’s
what is Kallman’s due to?
failure of production of GnRH
what would a thick endometrium suggest?
polycystic ovaries
what would a thin endometrium suggest?
decreased oestrogen
what investigations should all patients with oligo/amenorrhea have?
LH, FSH, oestradiol
thyroid function, prolactin
what is female hypogonadism identified by?
low levels of oestrogen
primary hypogonadism
problem with ovaries
secondary hypogonadism
problem with hypothalamus or pituitary
what would a high LH/FSH suggest in primary hypogonadism?
hypergonadotrophic hypogonadism
give an example of a cause of primary hypogonadism
premature ovarian failure
give an example of secondary hypogonadism
high PRL
hypopituitarism
what would an FSH > 30 suggest?
post-menopausal
give some examples of causes of POF
chromosomal abnormalities
gene mutations
autoimmune disease
iatrogenic
POF
premature ovarian failure
what chromosomal abnormalities could cause POF?
Turner’s syndrome
Fragile X
what gene mutations could cause POF?
FSH/LH receptor
what autoimmune diseases are associated with POF?
Addison’s
thyroid
APS1/2
what are the iatrogenic causes of POF?
radiotherapy
chemotherapy
what characterises secondary hypogonadism?
low estradiol and low/norma LH or FSH
what hypothalamic problems could cause secondary hypogonadism?
functional hypothalamic disorders
Kallman’s syndrome
IHH
IHH
idiopathic hypogonadotrophic hypogonadism
what other things could cause secondary hypogonadism?
Prader-Willi
Haemachromatosis
pituitary problems
what is IHH identified by?
absent or delayed sexual development associated with inappropriate low levels of gonadotrophin and sex hormone levels in absence of anatomical / functional defects of hypothalamic-pituitary gonadal axis
what is the only clinical difference between IHH and Kallman’s?
anosmia in kallman’s
what is the major defect in IHH?
inability to activate pulsatile GnRH secretion during puberty
Kallman’s syndrome
A genetic disorder characterised by a loss of GnRH secretion + anosmia or hyposmia
hyposmia
reduced ability to smell & detect odours
which sex is Kallman’s dynamo more common in?
males
what can cause loss of LH/FSH stimulation?
non-functioning pituitary macroadenoma
empty sella
pituitary infarction
non-functioning pituitary macroadenoma
pituitary tumour
pressure effects lead to hypopituitarism
empty sella
small or no pituitary gland normal pituitary function except loss of FSH/LH
what can cause hyperprolactinemia?
micro/macro prolactinoma
drugs
PCOS
polycystic ovarian syndrome
what are the oestrogen levels like in PCOS?
normal
what is the rotterdam criteria?
2 of:
menstrual irregularity
hyperadrogenism
polycystic ovaries
what is the rotterdam criteria used for?
diagnosis of PCOS
hirsutism
excess hair; usually used when referring to women with male pattern hair distribution
what is hirsutism caused by?
androgen excess at hair follicles
what can cause androgen excess at hair follicle?
- excess circulating androgen
- increased peripheral conversion at the hair follicle
what can cause hirsutism?
PCOS familial idiopathic non-classical congenital adrenal hyperplasia adrenal/ovarian tumour
CAH
congenital adrenal hyperplasia
what is CAH?
an inherited group of disorders charaterised by a deficiency in one of the enzymes necessary for cortisol synthesis
what is the inheritance pattern of CAH?
autosomal recessive
when is classic CAH typically diagnosed?
infancy
what is classic CAH due to?
21alpha-hydroxylase deficiency
what is non-classic CAH due to?
partial 21alpha-hydroxylase deficiency
what does non-classic CAH usually present with?
hirsutism
menstrual disturbance
infertility due to anovulation
when does non-classic CAH usually present?
adolescence/adulthood
anovulation
he failure of the ovary to release ova over a period of time generally exceeding 3 months
what is the karyotype of Turner syndrome?
22X
name some features of turner syndrome
short stature
webbed neck
shield chest with wide spaced nipples
cubitus valgus
XX gonadal dysgenesis
absent ovaries but no chromosomal abnormality
what is the most common congenital form of primary hypogonadism?
klinefelter’s syndrome
what’s they karyotype of klinefelter’s syndrome?
47 XXY
what could cause gynaecomastia?
physiological drugs tumours endocrine disorders systemic illness hereditary disorders
oligomenorrhea
cycles > 35 days
GnRH
gonadotrophin releasing hormone
what is GnRH synthesised by?
neurons in hypothalamus
what kind of release does GnRH exhibit?
pulsatile release
what does GnRH do?
stimulates FSH & LH
what happens to insulin in PCOS?
diminished biological response to a given level of insulin
twin-twin transfusion syndrome
unbalanced vascular communications within placental bed
