Sex Hormones :) Flashcards
define puberty
Maturation of reproductive organs
define thelarche
development of the breasts
define pubarche
pubic hair growth
-arche
onset of
define gonadarche
activation of gonads by the HPG axis (hypothalamic-pituitary-gonadal (HPG) axis)
define menarche
onset of menstrual cycles
define spermarche
onset of spermatogenesis
define spermatogenesis
the origin and development of the sperm cells within the male reproductive organs, the testes.
define adrenarche
adrenal androgen production
when does adrenarche start
2 years before gonadarche
what are the 2 key adrenal androgen hormones
DHEA/DHEAS
Testosterone
role of adrenal androgen
play a role in development of male sex organs and important for onset of female body hair following puberty
what is oestradiol
steroid hormone that matures and maintains the reproductive system
state the 3 components of puberty
- Production of sex-steroids i.e Oestradiol and Testosterone
- Develop secondary sexual characteristics
- Attain capability to reproduce
what is tanner staging?
the way we grade puberty (I= pre-pubertal and 5 = adult)
what 3 characteristics are taken into consideration in Tanner staging?
- thelarche
- genetalia => testicular vol in boys
- pubarche
how does the Tanner Staging regarding genetalia measure?
testicular volume in boys
what is the pre-pubertal testicular volume in boys?
< 4mls
what is the adult size testicular volume in men?
> 15mls
what is the first sign of puberty
gonadarche
what are the effects of oestradiol in women - 4
- thelarche
- hair growth
- sweat gland composition
- changes to external genitalia
what is axillary hair growth?
armpit hair
how is testicular size measured
using a Prader Orchidometer
how does the Prader Orchidometer work
compares testicular size to beads
state the 4 effects of testosterone in males
- deepening of voice
- hair growth
- sweat gland composition
- changes to external genitalia
what is the first sign of puberty in girls after gonadarche
thelarche
what is the late sign of puberty in girls
menarche
when does puberty occur in girls?
8-13 yrs
when does puberty occur in boys?
9-14 years
state the 2 gonads
ovaries and testes
trophin
to stimulate or grow
what does gonadotropin lead to the release of? - 2
LH and FSH
as the Tanner stage increases, what happens to gonadotropin levels
gonadotropin levels increase
why is adrenarche more important in girls?
girls do not produce testosterone so are more dependant on adrenal androgens
order of puberty progession in females
adrenarche => thelarche => growth spurt => pubarche => menarche
order of puberty progression in males
adrenarche => increase in testicular volume => pubarche => growth spurt => spermarche
order of puberty progression in males
adrenarche => increase in testicular volume => pubarche => growth spurt => spermarche
normal GnRH secretion is….
pulsatile
what does pulsatile mean?
released in bursts
why is pulsatility important
stimulates the pituatory gland
what would happen if GnRH wasn’t pulsatile?
decreased LH and FSH secretion
what does GnRH do
stimulates pituitary gland to make and release gonadotrophins
what does HPG stand for?
hypothalamic–pituitary–gonadal (HPG)
when is the HPG axis first activated
pre-puberty
what is mini-puberty
the activation of HPG axis shortly after birth
what is classed as an abnormal onset of puberty
mean +/- 2.5 standard deviations
what is precocious puberty?
early puberty before 8 years old
what is delayed puberty
late puberty after 14 years
what is amenorrhoea?
absence of periods for at least 3-6 months or up to 3 periods a year
what is primary amenorrhoea?
not ever having periods
what is secondary amenorrhoea?
when you have had periods but they have stopped.
why is mini-puberty important? - 4
- Sertoli cell maturation
- Behavioural effects
- Penile length
- Testicular descent
define peak height velocity
the period of time in which a child experiences the fastest growth
link between menarche and peak height velocity
menarche is often soon after individual reaches peak height velocity
amenorrhoea - age where it is abnormal
> 16 yrs
in the first 18 months are periods regular?
no
how many days is in a standard menstrual cycle
28 days
commonest cause of secondary amenorrhoea
pregnancy
what is the common variation between the menstrual cycle
+ or - 2 days for each person each month
what is oligomenorrhoea?
few periods
what is oligomenorrhoea?
irregular or infrequent periods
what is defined as oligomenorrhoea
> 35 days cycles
3 phases of the ovarian cycle
follicular phase => ovulation => luteal phase
what happens in the follicular phase?
Follicle stimulating hormone (FSH) rises => 2-3 follicles start to grow => Produce E2 (oestradiol) and Inhibin B => The restriction of the FSH window lead to the non-dominant follicles to undergo atresia => Dominant ‘Graafian’ follicle emerges => E2 continues to increase => inducing an LH surge
what does inhibin B do?
acts on the pituitary gland to reduce FSH secretion
what is the dominant follicle called
Graafian
what releases inhibin B
follicles
define atresia
degeneration of ovarian follicles
low oestradiol => feedback cycle
low oestradiol => -ve feedback to reduce FSH secretion
what is ovulation
when the egg is released from the follicle
as oestradiol increases what happens to the feedback loop?
increase in oestradiol => switch of -ve to +ve feedback to induce LH surge
what happens in ovulation?
LH increases => releasing egg from follicle
what induces ovulation
LH increase
when egg is released from follicle, what happens to the rest of the follicle?
under the action of LH the rest of the follicle becomes corpus luteum
what happens in the luteal phase?
formation of the corpus luteum
what does the corpus luteum produce? - 2
progesterone
oestradiol
role of progesterone
maintains the uterus lining
what is the role of oestrogen
thickens endometrium (lining of your uterus) for a fertilized egg to implant and grow
role of beta hCG
helps thicken a person’s uterine lining to support a growing embryo and tells the body to stop menstruation
what happens to testosterone and oestrogen production when there is decrease LH and FSH secretion?
decreased LH and FSH => decreased testosterone and oestrogen
impact of hypogonadism in men
decreased testosterone in a man
impact of hypogonadism in women
decreased oestrogen in women
what occurs in the primary conditions in endocrinology?
problem with gland that makes hormone
what is primary hypogonadism?
problem with testes or ovaries producing hormones
state the 3 phases of the endometrium-uterine cycle
menstrual phase => proliferative phase => secretory phase
what happens in the menstrual phase of the endometrium-uterine cycle?
shedding of the endometrium lining
what happens in the proliferative phase of the endometrium-uterine cycle?
Endometrial lining regrows => growth of new epithelial cells, gland proliferation and increase in stroma or arterioles
what hormone is involved in the proliferative phase of the endometrium-uterine cycle
oestradiol
what hormone is involved in the secretory phase of the endometrium-uterine cycle
progesterone
what happens to the no of stroma and arterioles in the proliferative phase
increases
what shaped glands produce glycogen in the secretory phase
cork-screw shaped
what happens to the arteries in the secretory phase of the endometrium-uterine cycle
coiling and lengthening
what happens to the volume of stromal cells in the secretory phase of the endometrium-uterine lining
increases
what does the stromal cells cause the endometrium to become
thick and spongy
what happens in secondary hypogonadism
problems with pituitary gland controlling LH and FSH secretion
what happens in tertiary hypogonadism
problems with the hypothalamus controlling pituatory gland
what does LMP stand for
last menstrual period
define menopause
period of a woman’s life in which menstruation ceases
define perimenopause
menopausal symptoms leading up to menopause
define post-menopause
after 1 year of menopause
what is the ovarian reserve
The total number of healthy, immature eggs in the ovaries.
define Premature ovarian insufficiency (POI)
menopause before the age of 40
define Late onset hypogonadism
decrease in free testosterone
what is a free hormone
active form of hormone not bound to proteins
why does free testosterone decrease as you age
bc increased SHBG
what is diurnal rhythm
biological rhythm that primarily express a periodicity during daylight hours
define Gynaecomastia
breast enlargement in men
if an embryo implants on the uterus lining - what hormone is produced
beta-hCG
what does beta-hCG act on and cause?
hCG acts on LH receptors => causes corpus luteum to survive and carry on making progesterone
role of LH in terms of corpus luteum
You need LH activity to form and maintain corpus luteum
if the embryo doesn’t implant what happens to progesterone levels
falls
can you measure GnRH in blood
no
whay is used to measure GnRH pulsatility in blood
LH
what menstrual phase has more frequent GnRH pulsatility
follicular phase
which menstrual phase has the less frequent pulsatility and why
luteal phase => because progesterone slows pulses
when there is decreased testosterone and oestrogen what happens
reduced -ve feedback => increased LH and FSH
What is the most common physiological cause of primary hypogonadism in women
menopause
state 3 causes of primary hypogonadism in MEN
cancer - leading to removal of testes
infection
trauma
what is secondary hypogonadism also called
hypogonadotrophic hypogonadism
what happens to gonadotropin levels in secondary hypogonadism
low
what hormones are low in secondary hypogonadism
low FSH and LH => low E2 and testosterone
state 3 causes of secondary hypogonadism
- pituatory tumor
- high prolactin
- hypothalamic amenhorrea (menopause)
define hypothalamic amenhorrea
when the hypothalamus slows or stops releasing gonadotropin-releasing hormone (GnRH)
what leads to hypothalamic amenhorrea
menopause
what are the hormone levels in menopause
decreased oestrogen => less -ve feedback => high LH and FSH
what is inhibin
a protein regulating the pituitary secretion of FSH.
what happens to inhibin levels in menopause
low
age range of menopause
45-55
state 7 symptoms of menopause
- Hot flushes
- Sleep disturbance
- Osteoporosis => joint pain
- Amenorrhoea
- Sexual dysfunction
- Weight gain
- Cessation of fertility
what therapy is often used to treat menopause
Menopausal Hormone Therapy
how does Menopausal Hormone Therapy work
replaces oestrogen
what is the impact of oestrogen on the endometrium
causes endometrium to proliferate
link between oestrogen and cancer risk
high oestrogen => increased risk of cancer
if given oestrogen replacement, what must be added to the treatment if endometrium is intact to decrease cancer risk?
progesterone
state 3 causes of premature ovarian insufficiency
autoimmune
genetic
cancer therapy
what hormone is used to reflect ovarian reserve
anti-mullerian hormone (AMH)
what produces AMH
granulosa cells in the ovaries
what is the levels of AMH at menopause
low
what does testosterone bind to?
sex hormone binding globulin (SHBG)
can testosterone unbind itself from SHBG
no
can testosterone activate itself to activate androgen receptors
no
what other protein in blood plasma can testosterone bind to
albumin
bioavailable testosterone
what type of rhythm does testosterone have
diurnal
when is testosterone highest in the day
morning before 11am
impact on testosterone after eating
decreases temporarily
state 7 impacts of testosterone deficiency
- Sexual dysfunction
- Erectile dysfunction
- reduced growth of hair
- mood disturbance
- changed body composition
- impacted spermatogenesis
- low testosterone = impact on bone health
what is the testosterone tissue effect in the prostate and scalp - state reaction conversion and enzyme
testosterone => Di-Hydro-Testosterone (DHT)
ENZYME: 5a-reductase
state the enzyme catalysing testosterone tissue effect in prostate and scalp
5a-reductase
state the enzyme catalysing testosterone tissue effect in adipose tissue
aromatase
state the testosterone tissue reaction in adipose tissue stating conversion and enzyme
testosterone => oestrogens
ENZYME = aromatase
impact of DHT on balding
increased DHT = increased balding
