Menstruation Flashcards
Sources and forms of estrogen?
Ovary: 17-B estradiol
Adipose tissue: Estrone via aromatization
Placenta: Estriol
Potency of estrogens in decreasing order?
Estradiol, estrone, estriol
What “growth” functions does estrogen have?
Development of genitalia and breast Female fat distribution Growth of follicle Endometrial proliferation Myometrial excitability
What hormonal effects does estrogen have?
Upregulation of estrogen, LH and progesterone receptors
Inhibition of FSH and LH (then LH surge)
Stimulates prolactin secretion
What is the effect of estrogen on transport proteins?
Increase TX proteins, SHBG, HDL.
Decreases LDL.
Where are estrogen receptors located in the cell?
Expressed in cytoplasm, translocate to nucleus when bound by estrogen
What changes occur in pregnancy to the levels of estradiol, estrone, and estriol?
50-fold increase in estradiol and estrone.
1000-fold increase in estriol –> indicator of fetal well-being.
What stimulates FSH and LH release from anterior pituitary?
pulsatile GnrH
What does LH stimulate?
Theca internal cell. Conversion of cholesterol to androgens via desmolase.
What does FSH stimulate?
Granulosa cell. Conversion of androgens to estradiol by aromatase.
Which cells are closet to egg?
granulosa (granny hugs the baby).
What are the sources for progesterone?
Corpus luteum, placenta, adrenal cortex, testes
What is the function of progesterone in the menstrual cycle?
Stimulation of endometrial glandular secretions and spiral artery development
What is the effect of progesterone on pregnancy?
Maintenance - pro-gestation.
What is the effect of progesterone on myometrium?
Decreases myometrial excitability, uterine smooth muscle relaxation, preventing contractions.
What is the effect of progesterone on the cervix?
Production of thick cervical mucus, which inhibits sperm entry into the uterus
What is the effect of progesterone on body temperature?
Increases
What is the effect of progesterone on estrogen receptor expression?
Decreases - prevents endometrial hyperplasia.
What is the effect of progesterone on gonadotropins?
Inhibits LH and FSH
What does fall in progesterone after delivery do?
Disinhibits prolactin –> lactation.
What happens during the follicular phase to the endometrium?
Proliferative phase - thickens.
What happens to the follice during the follicular phase?
Matures. Follicular growth is fastest during second week of proliferative phase.
What hormone predominates during the proliferative phase?
FSH and LH at beginning induce rising estrogen levels
What does rising levels of estrogen lead to?
LH surge
What does LH surge lead to?
Ovulation, followed by progesterone secretion from corpus luteum
When does the luteal phase/secretory phase begin?
After ovulation.
What is the role of progesterone in the luteal phase?
Maintains endometrium to support implantation.
When does menstruation occur?
If corpus luteum not fertilized, regresses, and progesterone levels fall.
By 14 days after ovulation, menstruation will begin.
How does menstruation occur?
Apoptosis of endometrial cells
What is a normal cycle length?
21-35days.
What is the cutoff for menorrhagia?
> 80mL blood bloss, >7 days of menses.
