Module 3 : Physiology Of Menstrual Cycle Flashcards
Menarche
The very first menstrual flow
Menses
Regular monthly flow in reproductive years
Perimenopausal
Women at the end of her menstrual years
- irregular cycle pattern
- late 40s
- 10 year duration
Menopause
When menstrual cycle ceases for 1 year
GnRF or GnRH
- Gonadotropin releasing factor or hormone
- produced by hypothalamus
- stimulates anterior pituitary to produce its hormones
Hypothalamus
Control center for the menstrual cycle
FSH and LH
- follicle stimulating hormone
- luteinizing hormone
- produced by BETA cells in anterior pituitary
- known as gonadotropins
- stimulate ovaries
FSH
- stimulates growth of follicles
- many follicles will be stimulates but only one follicle will mature with each cycle
LH
- Stimulates follicles but to a lesser extent compared to FSH
- SURGE IN LH RESPONSIBLE FOR OVULATION
- LH supports growth of corpus luteum but does not maintain it ( hCG maintains it in pregnancy)
Estrogen
- secreted from the GRANULOSA cells lining the follicle
- peak secretion occurs just before ovulation
- estrogen must hit threshold so LH can surge
- estrogen cause of proliferation of endometrium
- responsible for secondary sex characteristics
Corpus luteum
- after ovulation the remaining follicle become the corpus luteum
Progesterone
- Secreted by CORPUS LUTEUM
- peak concentration r ached 7 days after ovulation
- induces secretory activity and hypertrophy of endometrium
- inhibits secretion of LH
Relaxin
- Relaxes symphysis pubis during fetal delivery
- helps dilate the cervix to promote sperm mobility
- dilates the cervix in labor during fetal delivery
Stages of the cycle
Menstruation: day 1-5 (first day of a show of blood)
Proliferative phase: day 6-14 (follicular phase)
Ovulation: day 14
Secretory phase: day 14-28 (luteal phase)
Physiology of Menstrual Cycle
- day 1 is bleeding phase
- ovarian hormone levels are low causing hypothalamus produce GnRH
- causes pituitary to produce FSH and LH
- GRAAFIAN FOLLICLE (primary follicle) matures by day 13 and accompany an increase in estrogen
- estrogen hits a threshold which causes LH to surge and induces ovulation at day 14
- Graafian follicle bursts and become corpus luteum
- progesterone increase and estrogen decreases
- corpus luteum regresses if no fertilization occurs and progesterone decreases
- withdrawal of hormones causes menstruation to begin again
Symptoms
- mittelschmerz
- may have fluid retention or weight gain in luteal phase
- rise in body temp at ovulation due to progesterone
Proliferative phase - endometrium
- hypoechoic halo
- echogenic edge of endometrium
- hypoechoic endometrium in the proliferative phase
- apposing endometrial lining
- THREE STRIPE PHASE
Secretory phase - endometrium
- hypoechoic halo (basal layer)
- hyperechoic endometrium
Menstrual phase - endometrium
- endometrium very thin
- may even see blood within the canal
Postmenopausal endometrium
- very thin 1-5mm
- if greater than 5mm may be cancer
- on HRT endometrium thicker
Visualizing endometrium
- try to get perpendicular to endometrium
- retroflexed difficult to see endometrium
Corona radiata
Layer around the egg that giver nutrients
Zona pellucida
Doesn’t allow more fertilization to occur after first fertilization
Granulosa cells
Produce estrogen
