The Menstrual Cycle Flashcards
Quick review of the feedback loop of HPO axis:
GnRH produced by:____
FSH and LH by:_____
Sex steroids from the: _____
Hypothalamus
Anterior pituitary
Ovaries
The hirmone that is produced by the ovaries to inhibit secretion of anterior pituitary hormones is
Inhibin
The hormone that is produced by the ovaries to promote secretion of anterior pituitary hormone is
Activin
Which phase promotes the positive feedback?
Follicular phase
Which phase promotes the negative feedback?
Luteal phase
The hormones FSH, LH activates the anterior pittuitary to produce estrogen, progesteron and activin to reguylate the menstrual and ovarian cycle
True or false
FALSE
The hormones FSH, LH activates the anterior pittuitary [ovaries] to produce estrogen, progesteron and activin [inhibin] to reguylate the menstrual and ovarian cycle
True about GnRH
A. Reguylates secretion of FSH and LH
B. Secreted in cyclical manner to be effective
C. Released from the neurons within the anterior hypothalamus (arcuate nucleus of the median basal hypothalamus)
D. Both A and C
E. NOTA
D
Gonadotropins:
A. FSH
B. LH
C. GnRH
D. A and B
E. AOTA
D.
True or False
The structural similarity of FSH and LH is at the alpha subunit and variews at the beta subunit
True
FSH acts on ____ cells of the ovarian follices to stimulate ____ growth
Granulosa cells
Follicular growth
hence the name follicular stimulating hormone
LH acts on ____ (2) cells for the purpose of stimulating ovarian steroid production.
Theca and granulosa cells
The leutenizing hormone leutenizes both cells turning them into:
Granulosa-lutein cells
Theca-lutein cells
Give three examples of the sex steroids that is produced by the ovaries
- Estradiol
- Progesterone
- Androgen
Secretion is regulated by FSH
• For development of secondary sex characteristics at puberty
• Thickens endometrium during the proliferative phase
Estrogen
Secretion is regulated by LH
• Maintains endometrium during secretory phase
• Prepares endometrium for implantation ( during pregnancy)
Progesterone
The secretory phase is a phase of endometrial cycle‼️
• Regulated by LH
• At low concentrations, these are transported to the granulosa cells
for aromatization to estradiol & estrone (two-cell two-gonadotropin
mechanism of steroidogenesis)
• At high concentrations (such as in PCOS), they are converted to 5-alpha
reduced androgens that cannot be converted to estrogens and inhibit
aromatase activity (this causes the atresia of follicles)
Androgen
Interval of cyclical ovulation occurs at:
21 to 35-day intervals
How long cyclical ovulation almost lasts??
Clue: One generation
40 years