female reproductive physiology Flashcards
main female reproductive organs
ovaries containing ovarian follicles fallopian tube uterus - body cervix - opening of the uterus into the vagina vagina
structure of ovaries
surface
cortex and medulla
describe the surface structure of the ovary
connective tissue capsule covered with layer of simple cuboidal epithelium
describe the cortex of the ovary
peripheral part
connective tissue containing ovarian follicles
what is an ovarian follicle
one oocyte surrounded by single layer of cells
describe the medulla of the ovary
central part
connective tissue with blood vessels supplying the ovary
what are the 2 main functions of the ovary
oocyte production
steroid hormone production
oocyte production in the ovaries
one mature egg per menstrual cycle
~400 ovulated during entire reproductive lifespan
majority of eggs perish during the cycle
finite number, decreases with increasing age - starts at ~30y/o
steroid hormone production in the ovaries
oestrogen develops and maintains female 2y sexual characteristics
progesterone prepares endometrium for implantation
50% of testosterone produced by ovaries before menopause
when does primordial germ cell mitosis occur
fetal life only
primordial follicles arrested in the stage of 1st meiotic division until puberty
meiotic division of germ cells
1st meiotic division complete and 2nd division starts after puberty and leads to release of 1 2y oocyte in a menstrual cycle which is capable of fertilisation
2nd meiotic division completes after fertilisation of oocyte with sperm
describe the process of oogenesis
mitosis before birth
FSH, LH secretion at sexual maturity
early 1y follicle –> 1y follicle –> 2y follicle
1st meiotic division now completed
2y meiotic division starts 2y follicle –> graafian follicle containing 2y oocyte
corpus luteum
if no fertilisation –> corpus albicans
follicular development stages
primordial follicles
primary follicle
2y follicle
3y/graddian follicle
what is a primordial follicle
1y oocyte arrested in 1st meiotic division surrounded by 1 layer of squamous pre granulosa cells
what is a 1y follicle
oocyte surrounded by zona and cuboidal granulosa cells
what is a 2y follicle
increased oocyte diameter and multiple layer of granulosa cells
resumption of 1st meiotic division
what is a 3y/graffian follicle
follicular fluid between the cells which coalesce to form antrum (fluid filled space)
completion of first meiotic division to form 2y oocyte and start of 2nd meiotic division
chromosomal division during oogenesis
oogonium - 2n (46)
mitosis
primary oocyte - 2n
PUBERTY meiosis continues 2y oocyte - 1n larger (arrests in metaphase 2), 1n polar body smaller (no use) ovulation, sperm entry - 1n meiosis, fertilisation fertilised egg - 2n
endocrine control of female reproductive axis
hypothalamic-pituitary-ovarian axis
hypothalamic-pituitary-ovarian axis
hypothalamus releases GnRH
GnRH acts of anterior pituitary which releases FSH and LH
FSH and LH act on the ovary
ovary releases oestrogen and progesterone which both act on the uterus to coordinate the menstrual cycle
positive and negative feedback in the hypothalamic-pituitary-ovarian axis
oestrogen released by the ovary has +ve feedback on anterior pituitary and hypothalamus during day 12-14 to increase GnRH and FSH+LH release
oestrogen and progesterone have -ve feedback on hypothalamus and anterior pituitary for most of the cycle to reduce GnRH and FSH+LH release
what is the purpose of the +ve feedback in the hypothalamic-pituitary-ovarian axis
aids with mid-cycle ovulation
the ovarian cycle
first 1/2 (follicular stage) - FSH and LH released and levels increased
follicular development starts - 2y follicle to antral follicle stage
FSH levels stays relatively static, small peak mid cycle
during the 1st 1/2 oestrogen is produced which causes follicular development
+ve feedback of oestrogen as it reaches its peak results in LH surge mid cycle –> ovulation
luteal phase (2nd 1/2)
if a pregnancy doesn’t occur the follicle –> corpus luteum
rise in progesterone to prepare the lining for pregnancy after ovulation and oestrogen drops
w/o pregnancy the corpus luteum dies, oestrogen and progesteone drop and the lining is shed
follicular phase of the ovarian cycle
FSH causes follicle to mature and produce oestrogen - inhibits development of other follicles
ovulation phase of ovarian cycle
LH surge causes ovulation
follicle ruptures and releases 2y oocyte
luteal phase of ovarian cycle
ruptured follicle forms a corpus luteum and secretes progesterone and some oestrogen
menstruation phase of the ovarian cycle
if a pregnancy hasn’t resulted the corpus luteum degenerates and forms a corpus albicans
new ovarian cycle can begin
menstrual cycle - endometrial development
day 1 - thin endometrium due to bleeding
cycle progresses with increasing oestrogen, endometrium starts to thicken
reaches a certain thickness mid cycle
progesterone secretion causes changes in the blood vessels
day 28 - max thickness, if no pregnancy, lining is shed
what does oestrogen cause in relation to the endometrial lining
thickening of the lining
what does progesterone cause in relation to the endometrial lining
changes in the vasculature
also adds to the thickness
what is the name given to the changes in the endometrial lining caused by oestrogen and progesterone
decidualisation - changes to the endometrium in preparation for pregnancy
ovarian and menstrual cycle together
- pituitary releases LH and FSH causes ovarian cycle - divided into follicular and luteal phase
- ovary produces oestrogen and progesterone - oestrogen dominant in first 1/2 for the follicular phase and progesterone dominant in the luteal phase
- these cause resulting changes to the endometrium during the menstrual cycle
- at the end if there is no pregnancy, the endometrium is shed and a new cycle begins
which part of the pituitary releases LH and FSH
ANTERIOR
define amenorrhoea
no periods
1y or 2y
2y is where they have started then stopped for 6mths or more
reasons for amenorrhoea
problem with regulating hormones - low FSH/LH, high prolactin (hypogonadotropic hypogonadism)
problem with ovarian function
problem with uterus or outflow tract
causes for problems with regulating hormones
functional chronic medical conditions intracranial space occupying lesion infection or trauma drugs genetic
functional causes for problems with regulating hormones
XS weight loss/gain
over exercising
stress
chronic medical conditions - causes for problems with regulating hormones
DM
sarcoidosis
renal disease
TB
intrancranial space occupying lesions - causes for problems with regulating hormones
prolactinoma
tumours
cysts
infection/trauma causes for problems with regulating hormones
meningitis
intracranial bleed
Sheehan’s
drug causes for problems with regulating hormones
glucocorticoids
anabolic steroids
opioids
genetic causes for problems with regulating hormones
Kallmann’s syndrome
causes for problems with ovarian function
hypergonadic hypogonadism - high/normal FSH/LH
genetic ageing POI/POF chronic illness - AI radio/chemotherapy infection - TB, mumps oophoritis
genetic causes for problems with ovarian function
Turner’s syndrome
46X, fragile X
ageing causes for problems with ovarian function
steep decline in ovarian function past 35y/o
problems with uterus or outflow tract
congenital
iatrogenic
congenital causes for problems with uterus or outflow tract
absent uterus, vagina - lack of mullerian duct development (MRKH syndrome)
transverse vaginal septum or imperforate hymen - Mullerian duct fail to canalise
androgen insensitivity syndrome
iatrogenic causes for problems with uterus or outflow tract
uterine adhesions or synechiae (Asherman syndrome)
Radiotherapy - pelvic/cervical
management of amenorrhoea
life style changes
optimise control of medical illness
stop drugs or switch to alternatives
prolactinoma - medical treatment
intracranial SOL - surgical treatment
vaginal anomalies (septum/hymen) - surgical treatment
uterine adhesions - surgical division hysteroscopic
fertility preservation before radio/chemotherapy
fertility treatment - IVF w/ own or donor eggs
