Menstrual Cycle Flashcards
Menstruation is the regular ____________ of _______________ when _________________.
It is also called “periods”
Aim is to prepare the womb for implantation and conception
shedding of the uterine lining (endometrium)
pregnancy do not occur.
Menstrual cycle has 2 component:________ cycle & \________ cycle
It has 4 phases:list them
Ovarian; Uterine
menstrual, follicular/proliferative phase, ovulatory & luteal / secretory phase
Normal cycle length is _____ days (________)
Average duration of menses is _____ days (_____)
Normal estimated blood loss is approximately _____ ml (______)
Ovulation usually occurs on day _____
(36 hrs after the onset of mid-cycle LH surge)
28; 21 - 35
3-5 ; 2-8
30; 20-80
14
• Ovarian cycle: ______ and _______
• Uterine cycle: _______ and _________
Follicular & Luteal
Proliferative & Secretory
Ovarian Follicular development
• Fetus: ________ in 20 wks
• At birth: ___________
• At puberty: ————-
• Release during ovulation: ________
• At menopause: _________
6-7 million
1-2 million
300,000
400-500
virtually none
Hypothalamic role in the menstrual cycle
hypothalamus secretes _________ in a ________ fashion and its activity is first evident at —————
GnRH
pulsatile
puberty
Hypothalamic role in menstrual cycle
Follicular phase GnRH pulses occur ______
Luteal phase GnRH pulses occur every __________
hourly
90 minutes
Release of GnRH is modulated by –ve feedback by:
__________,_________
Release of GnRH is also modulated by external neural signals
steroids
gonadotropins
Follicular phase
Begins with ______ on day ____ of the menstrual cycle & ends with ____________
menses;1
ovulation
Follicular phase
• RECRUITMENT
FSH maturation of a ______________ “recruitment”
only ______ reaches maturity
cohort of ovarian follicles
one
Follicular Phase
SELECTION OF DOMINANT FOLLICLE
• Usually occurs on day _____
• It depends on
- the intrinsic capacity of the follicle to ________________
5-7
synthesize estrogen
Follicular Phase
As the follicle mature , there is increased estrogen leading to __________FSH
“-ve feed back on the pituitary”
the follicle with the ____________________ will continue to thrive
• The other follicles “that were recruited” will become _________
highest numbers of FSH receptors
Decreased
atretic
Follicular Phase
FSH ACTIONS
- _________
-mitogenic effect : increased No. of granulosa cells leading to __________ FSH receptor
-stimulates __________ activity
- __________ LH receptors
• ESTROGEN
Acts synergistically with ____ to
- ___________ and —————— in granulosa & theca cells
• LH Acts on ______ cells to increase uptake of _____________ and ________ that is converted to _________ and ————
recruitment; increased
aromatase; increased
FSH; induce LH receptors; induce FSH receptors
theca; cholesterol & LDL
androstenedione & testosterone
Aromatase activity
conversion of ___________ to ___________ “__________ and __________”
androgens; estrogens
estrone & estradiol
Two cell two gonadotrophin theory
with LH stimulation, the ovarian ______ cells produce ————- is converted by __________ cells into __________ under the stimulus of _______
theca; androgen; granulosa; estrogens
FSH
-INHIBIN
Local peptide in the _________
-ve feed back on _______________
Locally enhances ____-induced ___________ production
follicular fluid
pituitary FSH secretion
LH; androstenedione
ACTIVIN
Found in __________
Stimulates _______ induced __________ production
_____ease gonadotropin receptors
_____ease androgen
follicular fluid
FSH; estrogen
Increase; decrease
NEGATIVE FEEDBACK ON THE PITUITARY
• ______________ and _________ cause -ve feed back on pituitary FSH
• This mechanism operating since childhood
increased estradiol & inhibin
POSITIVE FEEDBACK ON THE PITUITARY
__________________________ (reaching a threshold concentration) leads to +ve feed back on the pituitary (facilitated by low levels of _______________ ) leading to a ____________ which leads to secretion of progestrone
Operates after puberty
+ve feed back on pituitary FSH
super increased estradiol
progestrone; LH surge
Pre-Ovulation period
LH SURGE
Lasts for ______
Ovulation occurs after ______
Accompanied by __________________ level
Triggers the resumption of meiosis
Affects follicular wall follicular rupture
Granulosa cells lutenization progestrone synthesis
48 hrs ; 36 hrs
rapid fall in estradiol
Luteal phase
___________ days
FORMATION OF THE ____________
LASTS 14
CORPUS LUTEUM
Luteal phase
Marked increase in ________ secretion
which peak ____ days after ovulation (day _____ )
Corpus luteum is sustained by _____\
progestrone
7; 21
LH
Luteal phase
Progestrone actions:
-suppress _____________ on the ipsilateral ovary
-__________ activity which increases basal body temp
-endometrial ————-
follicular maturation
thermogenic
maturation
Late luteal phase
_________ estrogen & progestrone leading to _________ FSH &LH
The new cycle starts with the beginning of _________
If pregnancy occurs , ________ secretion would help to maintain the corpus luteum
Decreased ; increased
menses
hCG
Uterine cycle
Endometrium has 3 layers
• _______ layer of the endometrium innermost layer
-Adjacent to the _________
-Unresponsive to __________
-Remains ____________________
Basal; myometrium
hormonal stimulation
intact throughout the menstrual cycle
Uterine cycle
Functional layer of the endometrium
Composed of 2 layers
-zona __________ aka ___________ layer
- _______________ layer aka __________ layer
compacta; superficial
Spongiosum; middle
Uterine Cycle
Follicular /proliferative phase
endometrial thickness from _____ to ________ (from one basalis to opposite basalis layer)
2 to 8 mm
Uterine cycle
Luteal /secretory phase
Progestrone - Mitotic activity is severely restricted
-Endometrial glands produce then secrete
glycogen rich vacuoles
-Stromal oedema
-Stromal cells enlargement
-Spiral arterioles develop, lengthen & coil
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