1
Q
What influences the timing of puberty?
A
genetics, geographic location (close of equator, low altitude and urban living = earlier), health, nutrition, vision
2
Q
What is the initial hormonal change that occurs in puberty?
A
nocturnal GnRH and LH pulsitility
3
Q
How long does it take for the physical changes of puberty to occur?
A
average 4.5 years
4
Q
What is the average age of menstruation?
A
13y
95% 11-15
5
Q
What is the first change in secondary sexual characteristics of puberty?
A
breast budding, then 6 months later pubic hair
6
Q
What is the age range in which 95% of girls will develop secondary sexual characteristics?
A
8.5-13y
7
Q
What is thelarche?
A
the first change of puberty, the development of breast buds
8
Q
When is the average onset of menarche after thelarche?
A
average 2.5 years
9
Q
What are the hormonal changes that occur in puberty?
A
GnRH stimulates LH and FSH
This occurs years prior to physical changes
10
Q
What does LH and FSH do in girls during puberty?
A
LH stimulates the theca cells (stromal cells) in the ovary to release oestrogen precursors
FSH stimulates the ovarian follicle to convert the precursors to estrogen
11
Q
What does LH and FSH do in boys during puberty?
A
LH stimulates the leydig cells to make testosterone
FSH stimulates the sertoli cells in the seminiferous tubules to make sperm
12
Q
When is typical onset of male secondary sexual charactaristics?
A
9-14
13
Q
How many stages if the Tanner stage are there?
A
5
1 is prepubertal anatomy
14
Q
What is classes as precocious puberty?
A
tanner stage 2 present
G <8
B <9
15
Q
What is classed as delayed puberty?
A
tanner stage 2 not present
G>13
B >14
16
Q
What is classed as primary amennorrhoea?
A
> 15y
or >3 years from thelarche
17
Q
Why is pubic hair not a reliable sign of HPO maturity?
A
pubic hair development is controlled by the adrenal gland production of DHEA-S and is independent of HPO axis
18
Q
What is does the rise in DHEA-S cause?
A
adrenarche - pubic hair, skin oiliness, acne, sweat gland development
19
Q
What is a hormone?
A
a cell product which is secreted into the peripheral circulation to exert its effects on distant target tissues
20
Q
What is endocrine target?
A
distant target
21
Q
What is paracrine target?
A
neighbouring cells
22
Q
What is autocrine?
A
cell releases substances to influence it’s own function
23
Q
What does LH do in Reproduction?
A
binds to the theca interstitial cells and stimulates production of androstenedione, DHEA and small amounts of testosterone
24
Q
What does FSH do in Reproduction?
A
binds to the granulosa cells and converts androstenedione to estrogen
25
What effect does inhibin have on the pituitary gland?
inhibits FSH release in
26
What kinds of chemical can hormones be?
peptides or steroid hormones
27
What is the difference in receptor sites of steroid and peptide hormones?
peptide receptor - on cell surface, water soluble hormones
steroid receptor - on cell nucleus, lipophyllic hormones
28
What are peptide hormones in female reproduction?
HCG, LH, FSH
29
What is the make up of the peptide hormones?
a common glycoprotein alpha subunit linked with a unique beta subunit
30
Which two peptide hormones are very similar in structure?
LH and HCG - produces from same gene grouping
31
Which hormones is HCG similar in structure to?
LH and TSH
32
How early can HCG be produced after LH surge?
7-9 days
33
What purpose does HCG have in early pregnancy?
1. stimulates the ovary via LH /HCG receptors to initiate steroidogenesis
2. maintains endometrial integrity and uterine quiescence
3. maintenence of CL until placenta can take over making steroids
34
What is a cause of postmenopausal HCG?
pituitary gonadotrophs can make small amounts
35
Where are steroid hormones made?
placenta
gonads
adrenals
36
How is estrogen made?
aromatisation of C19 androgens by aromatase
37
which organs have aromatase?
ovaries, adipose, brain, skin
38
What is E2 and where and when is it made?
estradiol - made by ovary in reproductive years
39
What is E1, when is it made?
estrone made during menopause
40
What is E3 and where and when is it made?
estriol, made during pregnancy by the placenta
41
what is testosterone converted into to be more potent?
dihydrotestosterone (DHT)
42
what converts testosterone to DHT and where?
5 alpha reductase in peripheral tissues prostate, skin, hair follicles, liver, brain
43
What makes DHEA, androstenedione and DHEAS?
adrenal gland
44
What is DHEAS?
sulphated dehydroepiandosterone
45
Where is andoestenedione made into testosterone?
peripheral tissues adipose, skin, liver
46
Where is SHBG made?
liver
47
What increases production of SHBG?
hyperthroidism, pregnancy, estrogen administration
48
Whats reduces SHBG production?
androgens, progestagens, GH and insulin, weight gain
49
where are steroids metabolised?
in the liver mainly, also the kidneys and intestinal mucosa
50
How are estrogens metabolised?
mainly in the liver
hydroxylation of estradiol to estrone or catechol estrogens
then conjugated to glucoronides or sulfates to be water soluble
then excreted in urine
51
Why can't you give oestrogens in women with liver disease?
unable to metabolise it and excrete it
52
Where is the hypothalamus found?
at the base of the brain just superior to the optic chiasm
53
What is the hypothalamus made up of?
a cluster of neuron cell bodies or nuclei
54
how do the neurons from the hypothalamus connect to the PPG?
directly through synapses - ADH and oxytocin
55
how do the neurons from the hypothalamus connect to the APG?
hormones are released into the blood vessels at the median eminence (part of the hypothalamaus)
and get to the APG via capillaries
56
What is the embryologic origin of the APG?
the ectoderm from invagination of the rathke pouch in the roof of the mouth
57
What is the embryologic origin of the PPG?
from the neural ectoderm
58
What is the embryologic origin of the GnRH neurons?
from the medical olfactory system
59
Where are the GnRH cell bodies and where do they travel and release to?
in the arcuate nucleus of the hypothalamus, axons travel to the median eminence and release GnRH into the portal system and drain directly to the APG
60
What occurs is you get sustained GnRH rather than pulsitile?
blocks LH and FSH - this is how zoladex works
61
What is the pulse cycle in the follicular phase of GnRH?
high frequency, low amplitude, stimulates LH production culminating in surge. mediated by estrogen (increases the frequency)
62
how often is an GnRH pulse in the follicular phase?
1-2 hourly
63
What does the GnRH frequency reduce to in the secretory phase? what mediates it?
once every 4 hours, progesterone
64
How does prolactin effect GnRH?
inhibits it's release
65
How does the frequency of GnRH effect LH and FSH release?
low frequency - FSH
high frequency - LH
66
What is the typical length of the menstrual cycle?
28 day +/- 7
67
What is the typical length of a period?
4 days +/- 2
68
What is the average blood loss in a pwriod?
20-60ml
69
What phases of ovarian and endometrial occur day 1-5 of cycle
early follicular
menstrual
70
What phases of ovarian and endometrial occur day 6-14 of cycle
late follicular
proliferative
71
What phases of ovarian and endometrial occur day 15-28 of cycle
luteal
secretory
72
When does the body temperature rise in the menstrual cycle?
with the LH surge
73
What are the three major cellular sources of the ovary from the embryo?
1. primordial germ cells from the endoderm of the yolk sac
2. the coelemic epithelial cells of the mesoderm
3. the mesenchymal cells rom the gonadal ridge (mesoderm)
74
What do the primordial germ cells become in the ovary?
the oogonia
75
What do the coelomic epithelial cells of the ovary become?
the granulosa cells
76
What do the mesenchymal cells of the gondal ridge become in the ovary?
The ovarian stroma
77
When does the genitalia become distinguishable in the fetus?
week 10-11
78
What occurs at week 12 in a female fetus?
a subset of oogonia enter meiosis which arrests at prophase I to become primary oocytes (stays there until until recruited in cohort of follicles)
79
What occurs each month to the primary oocytes?
in recruited primary oocytes meiosis I is completed and starts meiosis arrests in metaphase II
80
When is meiosis II completed?
with fertilisation only
81
What is the two cell theory?
LH binds to theca cell and stimulates production of androstenedione
this diffuses across the basement membrane of the theca cell into the granulosa cell
the granulosa cells is then stimulated by FSH to convert this to estradiol and estrone by aromatase
82
What is the order of follicular development?
primordial follicle
primary follicle
secondary
tertiary or antral follicle
graafian follicle or preovulatory
83
What is makes up a primordial follicle?
a oocyte arrested in meiosis surrounded by a single flat layer of granulosa cells
84
What is makes up a primary follicle follicle?
an oocyte surrounded by a pseudostratifed layer of granulosa cells and an accellular cost called the ZP
85
What is makes up a secondary follicle?
final oocyte with further increase in the granulosa cell layer which differentiates into the theca interna and the theca externa
86
What makes up a tertiary follicle and what is the other name?
a follicular fluid collection between granulosa cells creating a fluid filled space called an antrum
aka antral follicle
87
What is the the final stage of follicular development?
graafian or preovulatory
further fluid accumulation and rapid growth
88
when is the follicle GnRH independent?
up to the secondary follicle
89
how long does follicular development take?
over 3 months
90
What triggers a single dominant follicle to be chosen?
a small FSH rise
91
How does estrogen effect the granulosa cells in early follicle development?
enhances the effect of FSH producing more estrogen
92
What cells make inhibin B and what does this do?
the granulosa cells, inhibits FSH release by the APG which stops other follicles reaching preovulatory status in any one cycle
93
Why is FSH higher in women with waning ovarian function?
loss ovarian of inhibin production in the previous luteal phase means you get higher FSH (not inhibited as much)
94
What effect does the higher FSH have on waning ovarian function?
shorter follicular phase and more twins
95
What occurs at the end of the menstrual cycle to hormones?
abrupt drop in prog, estrogen and inhibin A from corpus
increase in FSH
96
What doe granulosa cells do in response to FSH?
increase in cell number and express aromatase producing estrogens
as the levels of estrogens rise.
In response granulosa cells develop LH receptors and produce small amount of progestrone
97
What does the progesterone do to the granulosa cells?
reduces G cell proliferation and slows follicular growth
98
What causes the LH surge?
towards the end of the follicular phase the rapid rise in estradiol triggers a switch from negative to positive feedback in the hypothalamus and APG
99
What occurs with the LH surge?
re entry of the oocyte into meiosis
100
how long after the LH surge onset does ovulation occur?
36-40 hours
101
What forms the corpus luetuem?
the remaining follicular cells after ovulation
102
What level of progesterone on day 21 is consistent with ovulation
>3ng/ml
103
how long should progesterone supplements be continued for if you remove the corpus luteum?
until 10 weeks
104
What hormones does the corpus luteum produce?
progesterone, estradiol and inhibin A
105
What does hCG do to the corpus luteum?
acts on the LH receptors to save it from atresia and start steroid production of progesterone
106
What is involved int he proliferative phase of the endometrial cycle?
glands become more tortuous and cells in the glandular lumen undergo pseudostratification.
ET 12mm max at time of LH surge
107
What occurs in the early secretory phase?
after ovulation
glycogen rich vacuoles develop and are expelled in line with implantation stimulated by progesterone
spiral arteries inctrease in number and coiling
108
What occurs in the menstrual phase of the endometrium?
progesterone drops, glands collapse, spiral arteries constrict, causing hypoxia.
prostaglandin F2alpha induces myometrial contraction and loss of endometrial functionalis layer
109
What is the name of the follicle which releases an egg and becomes the corpus?
graafian
110
where where and when do the do the neurons releasing GnRH migrate to the arcuate nucleus of the forebrain?
migrate from the the olfactory placode by 11 weeks gestation
111
Where do the axonal ends of the GnRH neurons extend to?
the median eminence and release hormones into the pituitary portal system
112
What do FSH and LH do?
stimulate release of the sex steroid hormones from the ovaries
113
When do oocyte levels peak?
5/12 gestation at 6-7 million
114
Why do levels of oocytes of the female fetus decline prior to birth?
the sex steroids create a negative feedback loop on GnRH and FSH LH and create apoptosis
115
How many oocytes does a fetus have a birth?
1-2 mill
116
When are FSH and LH levels highest post birth in the baby? what effect does this have?
3/12, increased sex steroids, white vaginal discharge, breast budding, PV bleeding, ovarian cysts
117
Why do neonatal FSHand LH levels rise initially?
as the estrogens from the placenta fall
118
When do neonatal gonadotrophin levels fall to prepubertal range?
1-2 years
119
what level should estradiol be in childhood?
<10pg/mL
120
What occurs with FSH LH and estradiol levels in childhood?
all low, can test LH and estradiol for precocious puberty
121
What levels should LH be in childhood?
<0.3mlU/mL
122
During childhood what happens to the ovaries?
follicular growth and atresia
123
How many oocytes remain at puberty?
300 000
124
What is the neonatal gynae anatomy ?
cervix large than fundus, uterus spade shaped.
endometrium is echogenic from sex steroids
ovarian cysts common
125
What is the childhood gynae anatomy?
uterus and cervix equal sizes, uterus more tubular shaped
126
What is the definition of puberty?
the transition from childhood to sexual and reproductive maturity. The period when the endocrine and gametogenic functions of the gonads first develop to the point where reproduction is possible
127
When is the average time for thelarche?
10 y
128
over what time frame does a female have a pubertal growth spurt?
3 years after thelarche
129
What age do DHEA values peak?
25
130
When does adrenarche occur in females and males?
8-10 in G
10-12 B
131
How does estrogen contribute to puberty breast development?
stimulates ductal growth
132
How does progesterone contribute to puberty breast development?
lobule and alveoli growth
133
134
Ellen's flashcards
flashcards
Decks in class (27)
# Cards
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Week 419
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Week 585
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Autoimmune medications and pregnancy11
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Landmark trials to date13
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Week 6253
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Week 7259
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Week 8232
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Week 9206
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Week 10364
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Week 258
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week 371
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Week one136
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Week 11237
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Week 12314
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Week 13381
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GONC 1395
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GONC 2259
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Week 16134
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Week 17410
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Week 18266
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Week 19347
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Week 20307
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Week 21430
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Week 22370
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Week 23298
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Week 24325
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Week 261
