Menstruation Flashcards
What is the normally time for ‘loss’?
2-8 days, standard is 5 days
what’s the average length of a menstrual cycle?
23 - 29 days (average is 29)
what’s the blood loss in menstruation?
60 - 80mls
What hormone does the hypothalamus release? And where does it act?
GnRH - gonodatrophin releasing hormone is released from the hypothalamus and acts on the anterior pituatary
What hormones are released from the anterior pitutary gland and where do they act?
Leutinising hormone and follicle stimulating hormone, these acts on the ovaries
FSH stimulates maturation of an egg within the follicle
What is released from the ovaries and where to they act?
Estrodiol (oestrogen) and progesterone and activin inhibin
these all have negative feedback on the pituary and hypothaamis
oestrogen causes endometrial proliferation
where is oxytocin released from?
the posterior pituitary
When does the menstrual cycle begin?
The first day of menstruation
What is the first half of the menstrual cycle?
The follicular phase - the follicles are developing and the endometrium is proliferating
How long is the follicular/ proliferative phase?
Variable!! Unlike the luteal phase which is always 14 days after ovulation
How do you work out the day of ovulation?
the length of the cycle take away 14 - because the luteal phase is always 14 days and begins with ovulation
Which hormones dominate in the follicular phase?
FSH and oestrogen - FSH stimulating the growing follicle and oestrogen (produced by the ovary) stimulating endometrial proliferation
What causes the egg to be released from the dominant follicle?
the LH surge (marks the beginning of the luteal stage
Which hormones dominant in the luteal phase?
Progesterone
how is progesterone produced in the luteal phase?
the follicle becomes a corpus luteam and lives for 14 days secreting progesterone. Progesterone stabilises the endometrium
