Menstrual Cycle Physiology Flashcards
Organs Associated with Menstruation
Ovaries
Uterus
Follicle Stages and Functions
Primordial Follicle: Pregranulosa cells and 4n DNA
Primary Follicle: Granulosa cells with 4n DNA
Secondary Follicle: Granulosa and Thecal cells with 4n DNA
Tertiary Follicle: Small antrum, Gonadotropin dependent, 4n DNA
Graafian Follice: Large antrum with steroidogenic Mural Granulosa cells and second polar body, 2n DNA
Periovulatory Period
Event, Cellular Secretions
Follicle ruptures through wall and loses cumulus cells
Luteinization occurs so CL starts making Progesterone and Estrogen
Granulosa cells make angiogenic factors to vascularize CL
hCG maintains CL after 14 days
Follicular Atresia
Granulosa cells and oocytes undergo atresia
Thecal cells stay to repopulate stroma
Menses Phase Hormone Levels
Estradiol lower than inhibin and FSH higher than LH
Proliferative Phase Hormone Levels
Estradiol increases causing proliferation and LH surge that causes ovulation
FSH peaks at ovulation
Secretory Phase Hormone Levels
Corpus Luteum makes lots of progesterone and estradiol
This decreases LH and FSH
Granulosa cells increase inhibins which decreases FSH
Hypothalamic-Pituitary Ovarian Axis
Stimulations and Inhibitions
GnRH stimulates AP to release LH/FSH
LH stimulates thecal androstenedione/progestins
FSH stimulates granulosal estrogen/inhibins/activins
Estrogen and Progesterone have (+) feedback on Hypothalamus and AP in high concentrations and (-) feedback at low concentrations
Inhibins have (-) feedback for FSH on AP Activins have (+) feedback for FSH on AP
Steroidogenesis Before Ovulation
LH acts on thecal cells to increase androstenedione
FSH acts on granulosa cell to increase aromatase to make Estradiol
Activins increase FSH which helps increase Estradiol
LH Surge
Cause and Effects
Caused by high levels of Estradiol causing positive feedback loop with Hypothalamus and Anterior Pituitary
Aided by Activins that increase ovarian estrogen
Steroidogenesis After Ovulation
LH acts on Granulosa Lutein cells to make Progesterone
LH acts on Thecal Lutein cells to increase Androstenedione
Used by Granulosa cells to make estradiol
Basal Body Temperature Hormonal Regulation
Estrogen decreases BBT
Progesterone increases BBT
Hormonal Actions on Endometrium
Estrogen, Progesterone and Gonadotropins
Estrogen causes proliferation of basal stroma, epithelium and connective tissue
Progesterone increases decidual cells, vascularization and engorges glands
Also opposes estrogen actions
Low levels of LH/FSH cause Zona compacta/spongiosa degradation in menses
Turner Syndrome
Description, Presentation and Hormone Levels
Congenital Hypogonadism caused by 45 X genotype
Presents with short stature, webbed neck and square chest
Causes ovarian failure that leads to increased FSH from decreased estrogen feedback
Polycystic Ovarian Syndrome
Presentation and Hormone Levels
Presents with hyperandrogenism, anovulation, infertility and polycystic ovaries
Shows increased LH, Testosterone, DHEA
Shows decreased FSH
