Menstrual Cycle Physiology Flashcards
Which cells in the ovarian follicle produce androgens?
Theca (interna) cells
Which cells int he ovarian follicle convert androgens to oestrogen?
Granulosa cells
Which enzyme is responsible for converting androgens to oestrogens?
Aromatase
What is the most potent oestrogen produced by the ovary?
Oestradiol
What is the importance of oestrogen in the development of a female?
Development of secondary sexual characteristics.
What is the name of the part of the cycle spanning day 1-12?
Follicular Hhase
What pivotal point occurs between days 12-14?
Ovulation
What is the name of the part of the cycle spanning day 15-28?
Luteal Phase
What process is the onset of the follicular phase (and the whole cycle)?
Menstruation
What hormone starts to increase as the follicular phase begins?
GnRH - from hypothalamus, causing release of FSH and LH from the pituitary gland.
What does Leutinising Hormone (LH) do?
Stimulates theca cells of the follicle to produce androgens.
What does Follicle Stimulating Hormone (FSH) do?
Stimulates the granulosa cells to convert androgens to oestrogen.
Causes maturation of follicles until a Graffian follicle emerges.
Rising levels of oestrogen in the follicular phase inhibit which hormone?
FSH
A peak of oestrogen triggers a surge in which hormone? What is the result?
LH - resulting in ovulation.
What effect does LH have on the follicle after ovulation?
Stimulates development into the corpus luteum.
What is released by the corpus luteum?
Progesterone
What is the effect of progesterone in the Luteal phase?
Induction of secretory activity in the endometrium, increasing thickness.
Besides preparing the endometrium for implantation, what other effect does progesterone have?
Increase in basal body temperature
Increased thickness of cervical mucus
Glandular development of breasts
Inhibiton of FSH and LH (in high levels)
If fertilisation does not occur, what happens to the corpus luteum?
Degeneration, dropping progesterone levels.
What is the result of the drop in progesterone following the degeneration of the corpus luteum?
Vasospasm in arterioles of the endometrium, causing necrosis and bleeding a.k.a. menstruation.
Following the drop in progesterone levels, what hormones are no longer inhibited?
LH and FSH - the cycle begins again.
