Menstrual Cycle Flashcards
How many ligaments support the ovaries?
- Ovarian, broad, and suspensory ligaments.
What are the three layers of uterine wall?
Perimetrium, myometrium (smooth muscle), endometrium (highly vascular mucosal layer).
How many eggs are there at birth?
2 million.
Define the menstrual cycle.
The shedding of uterine functional endometrium.
How long is the menstrual cycle?
2 days.
What are the 2 phases of the menstrual cycle?
Follicular phase (1-14 days). Luteal phase (15-28 days).
On day 1, what hormone does the hypothalamus produce.
Gonadotrophin releasing hormone (GnRH).
What is the role of GnRH?
It stimulates the anterior pituitary to release FSH and LH
On day 1, the primary follicle is surrounded by a single layer of cells, called…
Granulosa cells.
Granulosa cells proliferate, and produce an outer cell layer known as a…
Theca cell layer.
What hormone activates granulosa cells?
FSH.
What hormone activates theca cells?
LH.
Why do not all the follicles maintain growth?
Oestrogen initiates a negative feedback loop, causing a fall in FSH.
Give 2 functions of oestrogen between 1-14 days.
They mature follicles. Act on uterine endometrium, causing proliferation. Feeds back to hypothalamus, so pituitary stops producing FSH and LH.
What is the function of theca cells?
They produce an androgen precursor (androstenedione).
What is the function of granulosa cells?
They produce the enzyme aromatase, which converts androstenedione into estradiol
A large surge in LH on day 14 results in what?
Ovulation. Follicle ruptures, oocyte released from follicle.