Female Reproductive Cycle Flashcards
What is the function of FSH in the early follicular phase?
Promotes granulosa cell proliferation and both FSH and LH stimulate estradiol synthesis
What occurs in the late follicular phase?
Dramatic increase in estradiol due to increase in granulosa cells in dominant follicle
Estradiol acts on hypothalamus to increase GnRH pulse generator frequency and pituitary sensitivity to GnRH
This positive feedback causes the LH surge that promotes ovulation
What are the secretory products of the corpus luteum and their effects?
Progesterone - negative feedback on gonadotropin release from hypothalamus and pituitary
Estradiol - negative feedback to pituitary
Inhibin A - negative feedback to pituitary
What occurs when the corpus luteum fails?
LH secretion decreases, FSH increases
Coincides with the start of the rapid growth phase of the cohort of follicles being recruited for the next menstrual cycle
What can circulating levels of Inhibin B and Inhibin A be used for?
Inhibin B - clinical marker to assess FSH mediated granulosa cell function
Inhibin A - Assess LH-mediated corpus luteum function
What is the stratum functionalis?
Upper two-thirds of the endometrium which undergo changes during the menstrual cycle
Strongly influenced by hormones
What is the proliferative phase of the endometrial cycle?
Corresponds with increasing estradiol synthesis
Estradiol causes:
Growth factor production by stromal cells
Induces growth of uterine glands
Development and elongation of spiral arteries
Increases expression of progesterone receptors
What is the secretory phase of the endometrial cycle?
Coincides with luteal phase
Progesterone promotes differentiation of the endometrium and its secretory capacity
Net effect is to provide nutrients for the unattached embryo and to prepare the endometrium for implantation
What is the menstrual phase of the endometrial cycle?
Drop in circulating levels of estrogen and progesterone triggers menses
Spiral arteries undergo progressive rhythmic contractions/relaxations
Ischemia and capillary stasis insues
What is the role of Prostaglandin F2a in the menstrual phase?
Induces vasospasms of spiral arteries
Causes uterine contractions that aid in the expulsion of the desquamated tissue
What does estradiol promote in puberty in females?
Growth spurt
Breast development
Growth and maturation of female reproductive tract
What does estrogen stimulate the synthesis of*?
Thyroxine-binding globulin
Sex steroid-binding globulin
Corticosteroid-binding globulin
HDL
*more actions previously described
What are the nongenomic cardiovascular effects of estrogen?
Dilatation
NO production
What are the genomic cardiovascular effects of estrogen?
Decrease in atherosclerosis
Decrease in vascular injry
Increased endothelium growth
Decreased smooth muscle growth
What is menopause?
Cessation of menstrual cycles resulting from the decline in supply of functional follicles
