The menstrual cycle Flashcards
When does ovulation occur?
14 days before the next menses
When does the LH surge occur in reference to ovulation?
LH surge occurs 24-36 hours prior to ovulation
Changes in the endometrium in the luteal phase are direct effects of which hormone?
Progesterone
Describe NORMAL menstrual loss
4-6 days, flow peaks at day 1-2
<80ml of blood lost
No clots
No flooding
Describe the normal menstrual cycle
28 day cycle (or somewhere between 21-35 days)
No intermittent bleeding or bleeding after sex
What happens in the follicular phase of the menstrual cycle?
Pituitary releases LH and FSH
Follicle develops
Granulosa cells around the egg release oestrogen
Oestrogen causes thickening of the endometrium
What happens during the luteal phase of the menstrual cycle?
Starts after ovulation
Empty follicle becomes the corpus luteum
Corpus luteum produces progesterone
What does LH do?
LH acts on theca cells to produce androgens
(This is then converted to oestrogen by aromatase which is released from granulosa cells by the action of FSH)
Low LH levels cause theca cells to produce progesterone
What does FSH do?
FSH acts on granulosa cells to produce aromatase which converts androgens to oestrogen