Puberty And Menstrual Disorders Flashcards
(72 cards)
The menstrual cycle occurs with the maturation of what?
The HPO axis
What does GnRH stimulate?
FSH and LH from the anterior pituitary which stimulates estrogen and progesterone from the ovarian follicle
What hormones does the anterior pituitary secrete?
FSH, LH, TSH, prolactin, GH and ACTH
FSH and LH are synthesized and stored in which cell type?
Gonadotrophs
Which hormones does the posterior pituitary secrete?
Vasopressin and oxytocin
The normal ovarian cycle can be divided into which two phases?
Follicular and luteal phase
The follicular phase of the ovarian cycle begins with what?
The onset of menstruation and culminates in the pre-ovulatory surge of LH
The luteal phase of the ovarian cycle begins with what?
The onset of preovulatory LH surge and ends with the first day of menses
What do decreasing levels of estradiol and progesterone from the regressing CL of the preceding cycle initiate?
An increase in FSH by a negative feedback mechanism which stimulates follicular growth and estradiol secretion
What is the 2 cell theory of ovarian follicular development and estrogen production?
LH stimulates the theca cells to produce androgens (androstenedione and testosterone); FSH stimulates the granulosa cells to convert these androgens into estrogens
What suppresses LH and FSH levels during the luteal phase?
Negative feedback effect of elevated circulating estradiol and progesterone
If conception doesn’t occur, what happens to estrogen and progesterone levels during the luteal phase?
They decline near the end of the luteal phase as a result of CL regression; FSH will then rise which initiates new follicular growth for the next cycle
Which 5 peptides are secreted from the hypothalamus and affect the reproductive cycle?
GnRH, TRH, somatostatin, CRF, PIF
Estradiol enhances the hypothalamic release of which hormone to induce the mid cycle LH surge?
GnRH
What is the average age for menarche?
12.43 years
When does menarche occur?
Within 2-3 years after thelarche (breast budding) at tanner stage IV (rare before stage III)
What is primary amenorrhea?
No menstruation by 13 yo without secondary sexual characteristics OR by age 15 with secondary sexual characteristics
What is the average blood loss per menstrual period?
30cc (changing pad 3-6 times a day); >80cc has been associated with anemia
What is puberty?
The development of secondary sexual characteristics and the acquisition of reproductive capability
When does puberty usually occur?
Between 10-16 yo (mean is 12.4)
What are the factors that determine the onset of puberty?
Genetic factors including race; geographic location (girls that live in metropolitan areas, at altitudes near sea level begin earlier); nutritional status (obese will have early onset whereas malnourished will have later onset)
When does a female infant acquire the lifetime peak number of oocytes?
By mid gestation (16-20 weeks)
When is the HPO axis suppressed?
Between the ages of 4-10 years old
What is the gonadostat?
The hypothalamic-pituitary system regulating gonadotropin release